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!

I had this same problem June 28 2021 with xCode 12.5. I like to add a short descriptive comment at the start of a func() { But apparently it causes errors if the comment is not on a new line. The resulting error messages are very confusing. It cost me a few hours of misguided "fixes" and restoring from backups, before finding this forum post and explanation. Thanks for posting! Apple is overdue to fix this.

Patrick: thanks for posting your reply about "Removed from Sale" status and TestFlight. I updated an old app and successfully uploaded it for TestFlight testing. However, testers get the error message that it is not available or doesn't exist when trying to install it. Apparently it's because the old app is currently listed as "Removed from Sale". It was removed because it was developed using Flash based tools that don't meet App Store requirements. A similar update to another old app worked fine with TestFlight but it was still "Ready for Sale". My new version of the app using xCode 12.5 and SwiftUI tests OK when locally installed. So it appears that I have to submit it for App Store approval before it can be tested using TestFlight!!