OK. I logged in as my testdev admin and took screen shots of the previous archiving test that failed. I hope I got the report you asked for as it doesn't look similar to your example. I can still do archiving/codesigning with the same Apple account (and projects) on my wife's M1 MacBook Air. I spent many hours trying possible solutions over the last year. When I found the SEID mismatch I thought this might be causing codesigning to fail, as the mismatch is specific to my M4 Mac Mini. Thanks again MB

The test app failed when i tried to archive it, with the error "code signing failed with a non zero exit code". and the message in the screen shot. If Apple's servers now check the SEID to confirm the physical Mac the SEID mismatch on my Mac Mini M4 could explain why codesigning fails.

Please ignore the quote (above) re Managed Device Attestation. It is not relevant to this issue regarding standard App Store codesigning.

Case-ID: 20272957 As suggested, I logged in using a new admin account on my M4 Mac Mini, and then signed in to Xcode with my Apple account

I built and ran a test app successfully but archiving it failed. I tried this a few months ago with the same result. I noticed that Xcode can now automatically revoke any existing certificates. Although code signing failed, a new certificate and private key were created - but not paired I can still build, run, and archive Apps on my M1 MacBook Air using the same Apple account. I have tried a complete keychain reset, importing a p12 file from my MacBook Air, creating certificates manually and other ‘solutions’ suggested by AI help. I was surprised that you say that code signing is (only) a keychain process. I read your TN3137 document which explains your statement in excellent detail but it does not mention SEIDs My limited understanding is that the newer chips introduced an extra level of security. The hardware SEID and OS SEID are shown separately (and mismatched) on my M4 Mac mini but only the OS SEID is shown on my M1 MacBook Air. Gemini AI indicates that the SEID is used at the server to verify the physical Mac. "When an app or MDM profile uses Managed Device Attestation, it asks the operating system to generate an asymmetric key pair. Instead of storing that key pair in the standard user keychain where a local administrator or malicious script might try to intercept it, the operating system isolates it within the Secure Element chip. The key pair is signed by Apple’s servers alongside the SEID, ensuring that the enterprise server can verify the request came from that exact physical Mac motherboard, completely independent of the user's local software keychain configuration." If Apple’s server reads the OS SEID on my Mac mini it would not match the saved H/W SEID. Would this cause the server to refuse to sign the App? Thanks for taking time to review this non-urgent case. I used to manage a s/w support group so I appreciate how busy you must be. Michael Birch p.s. Apple Developer Support assigned me to 102877839447. I uploaded images etc as requested and got a generic reply. I switched to DTS code level support Case-ID: 20272957 you replied via this post

Refined SEID Analysis — Possible Data Corruption Rather Than Migration Error Closer analysis of the SEID discrepancy reveals a suspicious bit pattern: Hardware SEID: ...03DB... System OS SEID: ...FFDB... The lower byte DB is identical. Only the upper byte differs — 03 vs FF — a 6-bit difference where the upper 6 bits are all set to 1 while the lower 2 bits are preserved. This pattern is more consistent with a data corruption event during SEID registration than two unrelated values from different machines. Could a corrupted System OS SEID registration during Time Machine restore initialization explain why codesigning identity pairing consistently fails on this Mac Mini? Is there a way to force re-registration of the System OS SEID from the hardware SEID without a complete factory reset?

Additional Finding (using Claude AI) — Possible Secure Enclave SEID Mismatch Running system_profiler SPSecureElementDataType reveals a potential discrepancy between the hardware SEID and System OS SEID: SEID: 04472C8BB9209002413205682832707603DBF0E05E8753C1 System OS SEID: 04472C8BB92090024132056828327076FFDBF0E05E8753C1 These values differ at bytes 17-18 — 03DB vs FFDB. Could a SEID mismatch resulting from a Time Machine restore cause private keys to be generated with incorrect internal application labels, preventing codesigning identity pairing on an M4 Mac Mini? This would explain why the problem has persisted across multiple macOS versions and survived complete keychain resets — if the Secure Enclave was improperly initialized during the Time Machine restore, no software level fix would resolve it.

I’m still hoping that someone can explain under what circumstances xCode or KeyChain Access would generate a new certificate and private key that are not paired (code signed). My M4 Mac Mini was setup using a Time Machine backup but I lost the private key. I used Claude and Gemini AI to guide me but none of their ‘solutions’ worked. Their latest suggestion was to create this post. A complete factory reset and rebuild of my Mac Mini without using a Time Machine backup would probably solve the problem but without understanding what caused it.

Interim solution - I was able to Archive my project on my wife's Mac Air (which I had last used 2-3 years ago) and then upload the build for App Store approval from my new Mac Mini. I am also trying to recover my private key from a Time Machine backup of my old Mac and then import it to my new Mac I recommend the post The Care and Feeding of Developer ID - https://developer.apple.com/forums/thread/732320

The suggested links require saved private keys from my old computer. I don't have them. I assumed that transferring my backup to my new computer included the keys. I have used Key Chain Access to reset everything. I can see my Apps in Connect including Certificates, Identifiers and Profiles. Revoking old Certificates and recreating them isn't helping. Can my private key (signing identity) be recovered from my account. If not, what other options are available so that I can sign and Archive my Builds.

Thank you for the reply! I verified that Automatic signing is set. I am the one-man team as Computerade Products and the popup image is attached below -showing missing private key - although the certificates appear to be new (i.e. created on my new Mac). My Test-App project Run is OK but Archive gives the same message that started this post. I'm on xCode 16.1. CodeSign /Users/michaelbirch/Library/Developer/Xcode/DerivedData/Test_App-apijkfdxvfxogbdgkozhfjnvbifn/Build/Intermediates.noindex/ArchiveIntermediates/Test\ App/InstallationBuildProductsLocation/Applications/Test\ App.app (in target 'Test App' from project 'Test App') cd /Volumes/GAGA\ HDD/Gaga\ Home/SwiftUI\ Projects/Test\ App Signing Identity: "Apple Development: Michael Birch (9KD5TCGGHG)" Provisioning Profile: "iOS Team Provisioning Profile: *" (37ed6a51-3784-499b-a588-26bed42acfc6) /usr/bin/codesign --force --sign 15E4CD69B95A3AF856ADEE7574C15D70EFF3B535 --entitlements /Users/michaelbirch/Library/Developer/Xcode/DerivedData/Test_App-apijkfdxvfxogbdgkozhfjnvbifn/Build/Intermediates.noindex/ArchiveIntermediates/Test\ App/IntermediateBuildFilesPath/Test\ App.build/Release-iphoneos/Test\ App.build/Test\ App.app.xcent --generate-entitlement-der /Users/michaelbirch/Library/Developer/Xcode/DerivedData/Test_App-apijkfdxvfxogbdgkozhfjnvbifn/Build/Intermediates.noindex/ArchiveIntermediates/Test\ App/InstallationBuildProductsLocation/Applications/Test\ App.app error: The specified item could not be found in the keychain.

Still no luck, and now I'm getting a "No Certificates Available" message when I try to create a provisioning profile. When I check the status of my account and select team I see "missing private key". Apparently it did not transfer over to my new Mac from my old Mac. R Resetting the Key Chain and revoking old certificates did not seem to help. There should be a simple solution for anyone that transfers development files to a new computer.

I reset the Keychain and removed existing certificates and profiles so I can use xCode automatic signing. However, I am still stuck on this problem: missing keychain item and unable to create an archive. Please help!

This problem seems to be related to posts about Keychain Access showing certificates under the Certificates tab but not showing any under My Certificates because the Private Key is missing. I don't have the original Private Key or .p12 files from my old computer. I created new Certificates but they still don't show in My Certificates. The login keychain is unlocked but Archive still fails when trying to sign the build! Old projects build OK but they also fail when I attempt to archive them. Hoping someone has the key (pun intended) to solve this!

Apparently developers should save Keychain info in addition to using Backup to setup a new Mac. I did not! So I created new Developer and Distribution certificates and they show in Keychain Access. I use xCode automatic signing but I still get the ".. could not be found in the keychain" error. Suggestions to resolve this would be much appreciated!