Help with missing files on SecureAccess vault

Hi, I have been using a Cruzer 4Gb USB for a couple of years on a Mac, and had a Secureaccess vault through SanDiskSecureAccessV3_mac.app with about 8 MB of data in around 6 files.

All fine until yesterday when I connected the USB, fired up the app, and found My Vault empty although Finder Info says it has 7.6MB of files in it.  The encrypted vault subfolders appear to have files in them but the opening screen in the app shows the Vault as empty.  I downloaded the win.exe file to the USB and opened it on a Win10 computer and same outcome.  Shows empty Vault.

Any ideas gratefully received (please)!  Files will take forever to recreate, and yes I know I should have backups, but don’t have recent backup.

I thought at first my Mac had been hacked as this USB was connected at the time, but not open, but checks on the Mac show nothing unusua so farl, and no other files have gone missing.

I am also having the same problem. I have probably 400 GB of media files in my Vault on my Extreme SSD and it no longer appears on the Drive list when I sign into SecureAccess V3.02 on my Mac.