Damaged tree blob - What to do now?

Hi,

along with your solution I tried to prune the unused blobs but the error message got worse:

restic -r /run/media/xxxxxx/BACKUP1/backup_restic/ prune --max-unused=0
enter password for repository: 
repository 1ddea405 opened successfully, password is correct
loading indexes...
loading all snapshots...
finding data that is still in use for 4 snapshots
[0:00] 25.00%  1 / 4 snapshots
decrypting blob 6b414ec5152afcddb62e55d74de2f8c43877780c809bd8f65e7a597a365372dd failed: ciphertext verification failed
github.com/restic/restic/internal/repository.(*Repository).LoadBlob
	github.com/restic/restic/internal/repository/repository.go:204
github.com/restic/restic/internal/repository.(*Repository).LoadTree
	github.com/restic/restic/internal/repository/repository.go:728
github.com/restic/restic/internal/restic.loadTreeWorker
	github.com/restic/restic/internal/restic/tree_stream.go:37
github.com/restic/restic/internal/restic.StreamTrees.func1
	github.com/restic/restic/internal/restic/tree_stream.go:164
golang.org/x/sync/errgroup.(*Group).Go.func1
	golang.org/x/sync@v0.0.0-20200625203802-6e8e738ad208/errgroup/errgroup.go:57
runtime.goexit
	runtime/asm_amd64.s:1374

Did I something wrong ?

Regards.