Kopia UI can't open a repository anymore

Hello everyone.

I’ve used Kopia for many months. I’m on Windows 11. I have 3 repositories, they are all local repositories.

Now, one of them can’t be opened by Kopia UI anymore - instead the other two are ok.

So, I’ve tried to open it from a DOS shell, by the command:

kopia repository connect

and on the second attempt, it opened it.

Being connected, I tried the command:

kopia snapshot list

and it failed, with the messages:

Found too many index blobs (2061), this may result in degraded performance.

Please ensure periodic repository maintenance is enabled or run 'kopia maintenance'.
error listing all snapshot manifests: unable to find snapshot manifests: unable to load manifest contents: error loading manifest content: invalid checksum
at q1e6d1134f4918fec8007c4f12873a9c7-se21172b0e857259b13d offset 32 length 580/580: decrypt: unable to decrypt content: cipher: message authentication failed 

I think that these are two different messages, one related to manintenance, and another one, uncorrelated to the first, about a missing (or a corructed?) file…

Can anyone help me?

I need to be able to use Kopia UI, because I don’t have technical skill enough to use the command-line mode… (anyway, now the command-line doesn’t work even…)

Many thanks in advance…