I successfully installed macOS Tahoe 26 in June on a separate external partition. Now I want to update to beta 5, but when the Mac restarts to install the update, it shows the progress indicator for a minute or two, then boots again into the main partition which has macOS 15.6. Am I required to install it from scratch?

A user of my AppKit, document-based app brought to my attention that when setting it as the default app to open a certain file with extension .md (by choosing in the Finder "File > Open With > Other", then selecting my app and enabling "Always open with"), trying to open it with a double-click displays the warning "Apple could not verify [file] is free of malware that may harm your mac or compromise your privacy". This is what happens for me: When keeping the default app for a .md file (Xcode in my case), the file opens just fine. When choosing my app in the "File > Open With" menu, the file opens just fine in my app. But when setting my app as the default app (see above), the warning is displayed. From that moment on, choosing my app in the "File > Open With" menu doesn't work anymore. Selecting Xcode doesn't work either. Only setting Xcode again as the default app allows me to open it in Xcode, but my app still isn't allowed to open it. Is this a macOS issue, or can I do anything in my app to prevent it? Where should I start looking for the issue in my code?

In my app I use AVAssetReaderTrackOutput to extract PCM audio from a user-provided video or audio file and display it as a waveform. Recently a user reported that the waveform is not in sync with his video, and after receiving the video I noticed that the waveform is in fact double as long as the video duration, i.e. it shows the audio in slow-motion, so to speak. Until now I was using CMFormatDescription.audioStreamBasicDescription.mSampleRate which for this particular user video returns 22'050. But in this case it seems that this value is wrong... because the audio file has two audio channels with different sample rates, as returned by CMFormatDescription.audioFormatList.map({ $0.mASBD.mSampleRate }) The first channel has a sample rate of 44'100, the second one 22'050. If I use the first sample rate, the waveform is perfectly in sync with the video. The problem is given by the fact that the ratio between the audio data length and the sample rate multiplied by the audio duration is 8, double the ratio for the first audio file (4). In the code below this ratio is given by Double(length) / (sampleRate * asset.duration.seconds) When commenting out the line with the sampleRate variable definition in the code below and uncommenting the following line, the ratios for both audio files are 4, which is the expected result. I would expect audioStreamBasicDescription to return the correct sample rate, i.e. the one used by AVAssetReaderTrackOutput, which (I think) somehow merges the stereo tracks. The documentation is sparse, and in particular it’s not documented whether the lower or higher sample rate is used; in this case, it seems like the higher one is used, but audioStreamBasicDescription for some reason returns the lower one. Does anybody know why this is the case or how I should extract the sample rate of the produced PCM audio data? Should I always take the higher one? I created FB19620455. let openPanel = NSOpenPanel() openPanel.allowedContentTypes = [.audiovisualContent] openPanel.runModal() let url = openPanel.urls[0] let asset = AVURLAsset(url: url) let assetTrack = asset.tracks(withMediaType: .audio)[0] let assetReader = try! AVAssetReader(asset: asset) let readerOutput = AVAssetReaderTrackOutput(track: assetTrack, outputSettings: [AVFormatIDKey: Int(kAudioFormatLinearPCM), AVLinearPCMBitDepthKey: 16, AVLinearPCMIsBigEndianKey: false, AVLinearPCMIsFloatKey: false, AVLinearPCMIsNonInterleaved: false]) readerOutput.alwaysCopiesSampleData = false assetReader.add(readerOutput) let formatDescriptions = assetTrack.formatDescriptions as! [CMFormatDescription] let sampleRate = formatDescriptions[0].audioStreamBasicDescription!.mSampleRate //let sampleRate = formatDescriptions[0].audioFormatList.map({ $0.mASBD.mSampleRate }).max()! print(formatDescriptions[0].audioStreamBasicDescription!.mSampleRate) print(formatDescriptions[0].audioFormatList.map({ $0.mASBD.mSampleRate })) if !assetReader.startReading() { preconditionFailure() } var length = 0 while assetReader.status == .reading { guard let sampleBuffer = readerOutput.copyNextSampleBuffer(), let blockBuffer = sampleBuffer.dataBuffer else { break } length += blockBuffer.dataLength } print(Double(length) / (sampleRate * asset.duration.seconds))

I have a table view where each row has two labels, one left-aligned and one right-aligned. I would like to reload a single row, but doing so causes the right-aligned label to hug the left-aligned label. Before the reload: After the reload: Reloading the whole table view instead, or disabling automatic row height, solves the issue. Can a single row be reloaded without resorting to these two workarounds? I created FB13534100 1.5 years ago but got no response. class ViewController: NSViewController, NSTableViewDataSource, NSTableViewDelegate { override func loadView() { let tableView = NSTableView() tableView.translatesAutoresizingMaskIntoConstraints = false tableView.dataSource = self tableView.delegate = self tableView.usesAutomaticRowHeights = true let column = NSTableColumn() column.width = 400 tableView.addTableColumn(column) let scrollView = NSScrollView(frame: CGRect(x: 0, y: 0, width: 500, height: 500)) scrollView.translatesAutoresizingMaskIntoConstraints = false scrollView.documentView = tableView view = scrollView Timer.scheduledTimer(withTimeInterval: 2, repeats: false) { _ in print("reload") tableView.reloadData(forRowIndexes: IndexSet(integer: 2), columnIndexes: IndexSet(integer: 0)) // tableView.reloadData() } } func numberOfRows(in tableView: NSTableView) -> Int { return 5 } func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView? { let cell = NSTableCellView() let textField1 = NSTextField(labelWithString: "hello") textField1.translatesAutoresizingMaskIntoConstraints = false let textField2 = NSTextField(wrappingLabelWithString: "world") textField2.translatesAutoresizingMaskIntoConstraints = false textField2.alignment = .right let stack = NSStackView(views: [ textField1, textField2 ]) stack.translatesAutoresizingMaskIntoConstraints = false stack.distribution = .fill cell.addSubview(stack) NSLayoutConstraint.activate([stack.topAnchor.constraint(equalTo: cell.topAnchor, constant: 0), stack.leadingAnchor.constraint(equalTo: cell.leadingAnchor, constant: 0), stack.bottomAnchor.constraint(equalTo: cell.bottomAnchor, constant: 0), stack.trailingAnchor.constraint(equalTo: cell.trailingAnchor, constant: 0)]) return cell } }

A user of my app noticed that when using it to move a file to the trash on an USB drive, the trash doesn't show the file until unmounting the drive and mounting it again. I was able to reproduce it with one of my own USB drives, but with another USB drive it doesn't reproduce. All USB drives are formatted APFS. When moving a file to the trash from the Finder, both USB drives immediately list it in the trash. Is this a macOS bug, or am I doing something wrong? I created FB19941168. let openPanel = NSOpenPanel() openPanel.runModal() let url = openPanel.urls[0] do { var result: NSURL? try FileManager.default.trashItem(at: url, resultingItemURL: &result) print(result as Any) } catch { fatalError(error.localizedDescription) }

My app displays some text that should appear the same regardless of the container view or window size, i.e. it should grow and shrink with the container view or window. On iOS there is UILabel.adjustsFontSizeToFitWidth but I couldn't find any equivalent API on macOS. On the internet some people suggest to iteratively set a smaller font size until the text fits the available space, but I thought there must be a more efficient solution. How does UILabel.adjustsFontSizeToFitWidth do it? My expectation was that setting a font's size to a fraction of the window width or height would do the trick, but when resizing the window I can see a slightly different portion of it. class ViewController: NSViewController { override func loadView() { view = MyView(frame: CGRect(x: 0, y: 0, width: 400, height: 400)) NSLayoutConstraint.activate([view.widthAnchor.constraint(equalTo: view.heightAnchor, multiplier: 3), view.heightAnchor.constraint(greaterThanOrEqualToConstant: 100)]) } } class MyView: NSView { let textField = NSTextField(labelWithString: String(repeating: "a b c d e f g h i j k l m n o p q r s t u v w x y z ", count: 2)) override init(frame frameRect: NSRect) { super.init(frame: frameRect) textField.translatesAutoresizingMaskIntoConstraints = false textField.setContentCompressionResistancePriority(.defaultLow, for: .horizontal) addSubview(textField) NSLayoutConstraint.activate([textField.topAnchor.constraint(equalTo: topAnchor), textField.leadingAnchor.constraint(equalTo: leadingAnchor), textField.trailingAnchor.constraint(equalTo: trailingAnchor)]) } required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") } override func resize(withOldSuperviewSize oldSize: NSSize) { // textField.font = .systemFont(ofSize: frame.width * 0.05) textField.font = .systemFont(ofSize: frame.height * 0.1) } }

A user of my app brought to my attention that unless they select their ~/Library/Mail folder explicitly in an open panel, they get an error when scanning it inside my app. I can confirm that I also get a permission error when trying to scan it as a subfolder of ~/Library, but not if I select it directly. I'm assuming this is intentional, but it would be nice to have an explanation or some documentation that I can point my users to when they encounter what appears to them as a bug in my app. What makes this matter even more confusing is that selecting a folder in any open panel of an app gives the app access to it for the lifetime of the app, but after restarting the app, access is lost again (unless it has a bookmark to it). This was probably the reason why the user thought that it worked in another app but not in mine. This is the code I use to scan: let openPanel = NSOpenPanel() openPanel.canChooseDirectories = true if openPanel.runModal() == .cancel { return } let enumerator = FileManager.default.enumerator(at: openPanel.urls[0], includingPropertiesForKeys: nil) { url, error in print(url.path, error) return true } while let url = enumerator?.nextObject() as? URL { } And this the error related to the Mail folder: ~/Library/Mail Error Domain=NSCocoaErrorDomain Code=257 "The file “Mail” couldn’t be opened because you don’t have permission to view it." UserInfo={NSURL=file:///~/Library/Mail, NSFilePath=/~/Library/Mail, NSUnderlyingError=0x600002991470 {Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"}}

In the past I was always able to install every major macOS version on an external drive so that I can test my apps. But now I'm unable to install macOS Tahoe 26 on an external drive. Actually, as far as I'm aware, there are not even official links to macOS 26 installers, but only instructions on how to update to macOS 26 from an existing macOS installation. So I thought I'd install macOS 15 on a separate drive and then update to macOS 26, but whenever I run the macOS 15 installer, tell it to install on the external drive, and reboot after the setup process completes, my MacBook just boots into my main macOS partition as if nothing happened. 3 months ago I somehow managed to install macOS Tahoe beta 1 on an external drive, I don't remember how (but I don't think it was anything crazy); booting into that beta 1 partition and trying to update doesn't work either, as my MacBook again boots into my main macOS partition. I already asked help about the update problem one month ago here, but nobody replied. Could someone at Apple please provide instructions on how one is supposed to install macOS 26 on an external drive (if possible before it becomes available to the public)? Are we supposed to buy a separate Mac for every macOS version that we want to test our apps on?

While preparing automated screenshots with Xcode UI tests for the iOS 26 release, I noticed that this simple line of code app.buttons["myTabItem"].tap() doesn't always work, both on iPhone and iPad Simulator. In fact, it rarely works. Even when repeating the same test, mostly it fails on that line, but a few times it works and I can see the tab item change in the simulator. My main view looks like this: TabView { MyTab1() .tag(tag1) .tabItem { Label("label1", systemImage: "image1") } MyTab2() .tag(tag2) .tabItem { Label("label2", systemImage: "image2") .accessibilityIdentifier("myTabItem") } The error I get is Failed to tap "myTabItem" Button: No matches found for Elements matching predicate '"myTabItem" IN identifiers' from input In the given list of buttons, I see the tab items with their labels, but none of them seem to have an identifier, while other buttons have the correct identifier. I wonder how this can only sometimes work. I tried isolating the issue by iteratively commenting out parts of the SwiftUI code, but unfortunately the behaviour seems erratic. When a change results in the issue not happening anymore, undoing the last X changes often causes the issue to stay away, even with configurations that previously had the issue. I've already spent almost a whole day trying to find the root cause, but with such apparently random behaviour it has proven impossible. Of course, I cannot reproduce the issue with a fresh test project, so the only way to reproduce it with 95% probability is running my original project. Has anyone had the same issue, or does anyone know how I could debug this to find out what causes my UI test to not be able to tap another tab item?

After upgrading to macOS 26, I noticed that showing a Quicklook preview in my app is very slow. Showing small text files is fine, but some other files I've tried, such as a Numbers document, take about 30 seconds (during which the indeterminate loading indicator appears) before the preview is shown. When showing the preview of an app, such as Xcode, the panel opens immediately with a placeholder image for the Xcode icon, and the actual Xcode icon is shown only after about 25 seconds. During this time many logs appear: FPItemsFromURLsWithTimeout timed out (5.000000s) for: file:///.file/id=6571367.2/ (/) FPItemsFromURLsWithTimeout timed out (5.000000s) for: file:///.file/id=6571367.23684/ (/Users) FPItemsFromURLsWithTimeout timed out (5.000000s) for: file:///.file/id=6571367.248032/ (/Users/n{9}k) FPItemsFromURLsWithTimeout timed out (5.000000s) for: file:///.file/id=6571367.248084/ (/Users/n{9}k/Downloads) Failed to add registration dmf.policy.monitor.app with error: Error Domain=NSCocoaErrorDomain Code=4099 "The connection to service named com.apple.dmd.policy was invalidated: failed at lookup with error 159 - Sandbox restriction." UserInfo={NSDebugDescription=The connection to service named com.apple.dmd.policy was invalidated: failed at lookup with error 159 - Sandbox restriction.} Failed to register application policy monitor with identifier 69DDBDB4-0736-42FA-BA7A-C8D7EA049E29 for types {( applicationcategories, websites, categories, applications )} with error: Error Domain=NSCocoaErrorDomain Code=4099 "The connection to service named com.apple.dmd.policy was invalidated: failed at lookup with error 159 - Sandbox restriction." UserInfo={NSDebugDescription=The connection to service named com.apple.dmd.policy was invalidated: failed at lookup with error 159 - Sandbox restriction.} FPItemsFromURLsWithTimeout timed out (5.000000s) for: file:///.file/id=6571367.155797561/ (~/Downloads/X{3}e.app) It seems that Quicklook tries to access each parent directory of the previewed file, and each one fails after 5 seconds. Why is Quicklook all of a sudden so slow? It used to be almost instant in macOS 15. I created FB20268201. import Cocoa import Quartz @main class AppDelegate: NSObject, NSApplicationDelegate, QLPreviewPanelDataSource, QLPreviewPanelDelegate { var url: URL? func applicationDidFinishLaunching(_ notification: Notification) { let openPanel = NSOpenPanel() openPanel.runModal() url = openPanel.urls[0] QLPreviewPanel.shared()!.makeKeyAndOrderFront(nil) } override func acceptsPreviewPanelControl(_ panel: QLPreviewPanel!) -> Bool { return true } override func beginPreviewPanelControl(_ panel: QLPreviewPanel!) { panel.dataSource = self panel.delegate = self } override func endPreviewPanelControl(_ panel: QLPreviewPanel!) { panel.dataSource = nil panel.delegate = nil } func numberOfPreviewItems(in panel: QLPreviewPanel!) -> Int { return 1 } func previewPanel(_ panel: QLPreviewPanel!, previewItemAt index: Int) -> QLPreviewItem! { return url as? QLPreviewItem } }

I noticed that when I have a fullscreen window in macOS 26, sidebars look like they are cut off at the top: they suddenly stop where the title bar/toolbar would appear when moving the mouse to the top of the screen, leaving a wide empty gap. Am I the only one who finds this ugly? Is this intended, or is there a workaround? This is how it looks in fullscreen (the sidebar borders are not easy to distinguish, look for the drop shadow): And this when moving the mouse to the top screen border to show the menu bar: I created FB20291636. @main class AppDelegate: NSObject, NSApplicationDelegate, NSWindowDelegate { func applicationDidFinishLaunching(_ aNotification: Notification) { let splitViewController = NSSplitViewController() splitViewController.addSplitViewItem(NSSplitViewItem(sidebarWithViewController: ViewController())) splitViewController.addSplitViewItem(NSSplitViewItem(viewController: ViewController())) let window = NSWindow(contentViewController: splitViewController) window.styleMask = [.titled, .closable, .miniaturizable, .resizable, .fullSizeContentView] window.toolbar = NSToolbar() window.delegate = self window.makeKeyAndOrderFront(nil) } func window(_ window: NSWindow, willUseFullScreenPresentationOptions proposedOptions: NSApplication.PresentationOptions = []) -> NSApplication.PresentationOptions { return [.autoHideToolbar, .autoHideMenuBar, .fullScreen] } } class ViewController: NSViewController { override func loadView() { let stack = NSStackView(views: [ NSTextField(labelWithString: "asdf") ]) stack.orientation = .vertical stack.alignment = .leading view = stack view.frame = CGRect(x: 0, y: 0, width: 300, height: 300) } }

I'm using the simplified code below to create a window with 4 split view items, some of them collapsed. I would expect the title bar to be transparent since I'm using window.titlebarAppearsTransparent = true, but it seems that this particular view configuration causes the title bar to be visible until I collapse and expand the sidebar again. Removing any of the split view items, uncollapsing any of them, or changing the view of any of the view controllers, causes the title bar to be consistently visible or hidden, although I don't understand the logic, since I'm telling the window that it should be transparent. When launching the app in light mode, it's more difficult to notice the issue since the title bar background is equal to the content background and only the separator is visible (even though the code sets window.titlebarSeparatorStyle = .none): After collapsing and expanding the sidebar, the separator is gone: In dark mode the title bar is more visible: After collapsing and expanding the sidebar, the title bar background and separator are gone: I created FB20306872. @main class AppDelegate: NSObject, NSApplicationDelegate, NSToolbarDelegate { var splitViewController: NSSplitViewController! func applicationDidFinishLaunching(_ aNotification: Notification) { let splitViewItem1 = NSSplitViewItem(sidebarWithViewController: ViewController1()) let splitViewItem2 = NSSplitViewItem(viewController: ViewController2()) let splitViewItem3 = NSSplitViewItem(viewController: NSViewController()) splitViewItem3.isCollapsed = true let splitViewItem4 = NSSplitViewItem(viewController: NSViewController()) splitViewItem4.isCollapsed = true splitViewController = NSSplitViewController() splitViewController.splitViewItems = [splitViewItem1, splitViewItem2, splitViewItem3, splitViewItem4] let window = NSWindow(contentViewController: splitViewController) window.styleMask = [.titled, .closable, .miniaturizable, .resizable, .fullSizeContentView] window.titlebarAppearsTransparent = true let toolbar = NSToolbar(identifier: "") toolbar.delegate = self toolbar.displayMode = .iconOnly window.toolbar = toolbar window.titlebarSeparatorStyle = .none window.makeKeyAndOrderFront(nil) } func toolbarAllowedItemIdentifiers(_ toolbar: NSToolbar) -> [NSToolbarItem.Identifier] { return [.space, .flexibleSpace, .sidebarTrackingSeparator, .init("item")] } func toolbarDefaultItemIdentifiers(_ toolbar: NSToolbar) -> [NSToolbarItem.Identifier] { return [.init("item"), .sidebarTrackingSeparator] } func toolbar(_ toolbar: NSToolbar, itemForItemIdentifier itemIdentifier: NSToolbarItem.Identifier, willBeInsertedIntoToolbar flag: Bool) -> NSToolbarItem? { switch itemIdentifier.rawValue { case "item": let item = NSToolbarItem(itemIdentifier: itemIdentifier) item.image = NSImage(systemSymbolName: "sidebar.leading", accessibilityDescription: nil) item.action = #selector(toggleSidebar(_:)) item.target = self return item default: return nil } } @objc func toggleSidebar(_ sender: Any?) { splitViewController.splitViewItems[0].animator().isCollapsed = !splitViewController.splitViewItems[0].isCollapsed } } class ViewController1: NSViewController { override func loadView() { view = NSView(frame: CGRect(x: 0, y: 0, width: 300, height: 200)) } } class ViewController2: NSViewController { override func loadView() { let textView = NSTextView() let scrollView = NSScrollView(frame: CGRect(x: 0, y: 0, width: 400, height: 200)) scrollView.hasVerticalScroller = true scrollView.documentView = textView view = scrollView } }

In macOS 26 I noticed there is a section Menu Bar in System Settings which allows to toggle visibility of status items created with NSStatusItem. I'm assuming this is new, since I never noticed it before. Currently my app has a menu item that allows toggling its status item, but now I wonder whether it should always create the status item and let the user control its visibility from System Settings. Theoretically, keeping this option inside the app could lead to confusion if the user has previously disabled the status item in System Settings, then perhaps forgot about it, and then tries to enable it inside the app, but apparently nothing happens because System Settings overrides the app setting. Should I remove the option inside the app? This also makes me think of login items, which can be managed both in System Settings and inside the app via SMAppService. Some users ask why my app doesn't have a launch at login option, and I tell them that System Settings already offers that functionality. Since there is SMAppService I could offer an option inside the app that is kept in sync with System Settings, but I prefer to avoid duplicating functionality, particularly if it's something that is changed once by the user and then rarely (if ever) changed afterwards. But I wonder: why can login items be controlled by an app, and the status item cannot (at least I'm not aware of an API that allows to change the option in System Settings)? If the status item can be overridden in System Settings, why do login items behave differently?

macOS 26 sometimes draws the title bar background even when setting NSWindow.titlebarAppearsTransparent = true and I don't understand the logic behind it, or how I can turn this off. I'm trying to do something similar to Xcode's "Welcome to Xcode" window which has a left view and a right table view. In my simplified example, the window contains a label and a text view. This used to work in macOS 15, but in macOS 26 the text view is partially covered by the title bar: As soon as I remove the line scrollView.hasVerticalScroller = true, the title bar isn't drawn anymore: The title bar also isn't drawn when removing the view on the left of the text view: I created FB20341654. This may be related to this other issue: NSWindow.titlebarAppearsTransparent only works after collapsing and expanding sidebar @main class AppDelegate: NSObject, NSApplicationDelegate { func applicationDidFinishLaunching(_ aNotification: Notification) { let window = NSWindow(contentViewController: ViewController()) window.titlebarAppearsTransparent = true window.titleVisibility = .hidden window.styleMask = [.titled, .closable, .fullSizeContentView] window.makeKeyAndOrderFront(nil) } } class ViewController: NSViewController { override func loadView() { view = NSView(frame: CGRect(x: 0, y: 0, width: 400, height: 200)) let scrollView = NSScrollView() scrollView.hasVerticalScroller = true // commenting this line out solves the issue scrollView.translatesAutoresizingMaskIntoConstraints = false scrollView.automaticallyAdjustsContentInsets = false let documentView = NSTextView() documentView.string = (0..<10).map({ "\($0)" }).joined(separator: "\n") scrollView.documentView = documentView let stack = NSStackView(views: [ NSTextField(labelWithString: "asdfasdfasdfasdf"), // commenting this line out also solves the issue scrollView ]) stack.orientation = .horizontal view.addSubview(stack) NSLayoutConstraint.activate([stack.topAnchor.constraint(equalTo: view.topAnchor), stack.leadingAnchor.constraint(equalTo: view.leadingAnchor), stack.trailingAnchor.constraint(equalTo: view.trailingAnchor), stack.bottomAnchor.constraint(equalTo: view.bottomAnchor)]) } }

I have an iOS app with a QuickLook extension. I also added Apple Vision Pro in the target's General > Supported Destinations section. About one year ago, I was able to run the app on iPhone, iPad and Apple Vision Pro Simulators. Today I tried running it again on Apple Vision Pro with Xcode 26.0.1, but Xcode shows this error: Try again later. Appex bundle at ~/Library/Developer/CoreSimulator/Devices/F6B3CCA8-82FA-485F-A306-CF85FF589096/data/Library/Caches/com.apple.mobile.installd.staging/temp.PWLT59/extracted/problem.app/PlugIns/problemQuickLook.appex with id org.example.problem.problemQuickLook specifies a value (com.apple.quicklook.preview) for the NSExtensionPointIdentifier key in the NSExtension dictionary in its Info.plist that does not correspond to a known extension point. I tried again later a couple times, even after running Clean Build Folder Immediately, without any change. I can reproduce this with a fresh Xcode project to which I add a Quick Look Preview Extension and Apple Vision Pro as a supported destination. The error doesn't happen when running on Apple Vision Pro (Designed for iPad) or iPad Pro 13-inch (M4) destinations. What is the problem? I created FB20448815.