Issue restoring a backup file QB 2020

Client sent over a QB 2020 backup file (at least he says it's 2020) via Dropbox.  When I go to restore, it tells me that I need to make a backup of the file so that I can upgrade, which is confusing as he says he's using 2020 (note that he's on a Mac while my PC is Windows, but he converted the file to Windows before he sent over).  When I go to make the backup so I can upgrade, it wants to store the new backup to a QB2005 folder on my PC.  

When I start the upgrade/backup process, it gets to 37% then I get an Unrecoverable Error.  Can't figure out what's going on. Client says that his file is good, so I'm wondering if it's something on this end.  FYI, I did try to restore on older versions of QB and have the same issue.