Every 2-3 monts I receive a .ptb sage 50 back up file from my client, I Restore it and do what i need to do.  I do not pass the data file back to the client.  They send me the data file on a thumb drive.

This month I am receiving "The file you have selected is not a valid sage 50 backup file..." . i have had them -backup to internal hard drive and then copy to thumb drive to deliver to me -I have copied the .ptb data file to my desktop to restore from -when failed I have moved the company folder away and retried restore (same failure).  

we are both running Sage 50 27.2.00.0219 with tax of 20200702

I have my sage 50 data on a server and am attempting the restore there.  the client has sage 50 on a stand alone pc.

Please advise