I am as of yet unsure if this is actually both related, but since some days, windows tries to run a disk check on every reboot. Checking the Logs, it appears to have found broken index in “$I30”… What is curious, is that in the log a truncated “~urbackup” is appearing:
Der Signatur des Multisektorenheaders für die virtuelle Clusternummer (VCN) 0x0 von Index $I30 in der Datei 0x230b0 ist nicht korrekt. 7e 75 72 62 61 63 6b 75 ?? ?? ?? ?? ?? ?? ?? ?? ~urbacku…
At this point I got suspicious and wanted to check the CBT status, which throws the following error:
If I click continue, the drive “D:” is listed twice
I am running the CBT 2.5.24 Client on my machine. The drives are Bitlocker encoded. I’ve also uploaded the Chckdsk error-log.
I’ve tried to delete the folder on the path in the log, but windows won’t let me delete it (it acts as if it deletes it, but leaves some folders in place. 
chkdsk_log.zip (1.9 KB)
Edit: Quick Update: After several attempts to fix the issue with chckdsk (see log attached) I deleted the UrBackup-Client and rebooted. Windows promptly did a repair again once windows was booting, only this time it actually seems to have repaired the filesystem (see log chkdsk_log_after_deleting_Urbackup.zip). In fact, after booting into windows, I was able to delete the folder which contained the broken index.
My assumption is, that CBT broke something in the filesystem and somehow locked access to this part. I’m not sure why or how though… I’ll try reinstalling the CBT client once I’m back from vacation and see if this happens again.
chkdsk_log_after_deleting_Urbackup.zip (11.0 KB)