You have entered an invalid name. Pls try again

I am using SanDisk SecureAcess 2.0.  Today, when trying to read the thumb drive, I get an error message “You have entered an invalid name.”

Following that, it get access into the vault and another error message appear. “This vault could not be loaded, it may be located on another computer or the original vault file has been manually removed”.

I have 2 Sandisk thumb drive and both drive has different data in it.

I am able to do a backup and restore but still unable to get access into the vault.

I notice that my vault file size is still relatively big at 26.6G.  I am using a 32G thumb drive.

Pls help and advice