Sandisk Secure Access not updating files during backup

Hello. I have 9 Sandisk Cruzer 4GB drives that I utilize for daily and archival backup of important documents.

Those documents exist in a specific folder. Every morning, I pop that day’s Cruzer into my USB drive, log into Sandisk Secure Access  Manager, and physically ADD the folder using ADD FILES.

Which means the version of updated files from the prior week are normally overwritten with the new versions. Which is perfect.

But after awhile, this stops happening. The updated files are NOT copied over. For example, a file updated 4/16/2016 should have overwritten the file on the Cruzer dated 02/06/2016. But it did not. The 02/06/2016 version is still there. I have checked, and the Cruzer still has a gig of free space. So the cause is not the Cruzer running out of space.

If I try to delete the files from within the Sandisk Secure Access Manager, nothing happens. Yes, it acts like it is processing the deletions, but after it completes all the files are still there. So I need to delete the vault itself and re-install Sandisk Secure Access  Manager altogether.

It is not only frustrating to have to reintsall Sandisk Secure Access Manager,  but I also have to look every day to see if the files copied properly. If I forget to check, then I may go weeks before realizing my daily routine has not been moving the files onto the cruzer.

Is there some sort of software upate I can download? Is this a known issue? Please advise. Thanks.

not sure what version you ahve but the latest version is version 3. download lins below