Error while exploring full backup

[clsmoreira]

Hello,

My setup:
- Daily full backup, and keepbackups for 7 days, on an external drive connected via USB.
- Once a week I intend to save the most recent full backup on a pen drive. Even if I also copy the file with the metadata (*.vbm) to the pen drive, when I explore the full backup I get the error: "Cannot find backup metadata file". If I explore the same file on the external drive, there is no error.

Why?

Questions:
- Do I always need to have the metadata file to be able to explore or restore a backup?
- Since it's a full backup, why doesn't it open on the pen drive, even though a full backup doesn't depend on any other backup?

Thank you.