HowTo: Backup MAS Certificates for clean macOS installation?

I would like to to completely wipe my MacBook and do a clean installation of Sierra. Can i somehow make a Backup of all my MAS Certificates, so that i can Restore them on my new macOS? Has anyone done this before and share your experience, please?

Would it be ok to just export the Cert’s AppWrapper Codesigning Diagnostics reports, as .cer Files. Will i be able to just import them again on my new Sierra Installation and will i be able to use them again?

You can use the technique described at the following link:
http://ohanaware.com/support/index.php?article=developerID_on_sierra.html

Just select all your certificates, not only the Developer ID certificates.

Thank you Sam :slight_smile:

Make a full backup so you can copy missing items from backup!

You can always copy items from old keychain to new one.

[quote=344103:@Christian Schmitz]Make a full backup so you can copy missing items from backup!

You can always copy items from old keychain to new one.[/quote]

I installed Sierra, downloaded Xcode and downloaded my Certificates using Xcode.

I thank you both. :slight_smile:

BTW: I forgot I can’t use my High Sierra TimeMachine Backups after a Downgrade to Sierra. :wink: