Acronis .tib files

I have previously used Acronis True Image 9. When creating backups, I never password protected.

When in Restore mode with Comodo, it is happy to select an Acronis.tib backup file, but Comodo then asks for a password.

I presume this is a password that Acronis labels with their .tib files, which is not apparent when restoring using Acronis.

Any idea what this password is?

If you try to open a file that is not in CBU format, then COMODO BackUp will asume the file is encrypted.
The application doesn’t ask for a password only when a file is in CBU format and it isn’t encrypted (it doesn’t matter if you change file extension).
This way, no one can force you to say the password for an encrypted backup file.