Hi I have a MacBook Pro, and since the last OS X update kept get error message and I couldn't gain use of the MacBook unless I turned it on and off, *** per Apple support I reinstalled the OS X operating system again this has made no difference.
That is just a few examples of the error messages, you clear one and the next one comes up.
MacBook Pro 15”, macOS 10.15
Maybe someone else will have a better way of having you repair or delete the Keychain (assuming only the Keychain is affected), but if not here is what I suggest:
If you reinstalled macOS over top of itself, then it means you will need to go for a more drastic option of erasing the drive and restoring from a backup made before this issue occurred, or you will need to perform a clean reinstall of macOS and manually transfer your data from a backup and manually reinstall your third party apps.
Make sure you have a good backup before erasing the drive or you will lose all your data.
Constant error message since last OS X update only remedied by turning MacBook off
