I backed up my QuickBooks info. for my accountant on a flash drive with a dividing date of 12/31/18. He made changes and gave me the flash drive back. I tried to import his changes from the flash drive. I lost all info. from 12/31/18 - the date I received the flash drive back. Also, I am unable to remove the flash drive as that file will not open without the flash drive in????
Flash drives are okay to transport files but you should always open or restore from your hard drive. You need to move or copy the change file which is what he should have provided to your PC drive, then import the changes.
This is presuming you made a correct accountant's copy file,not just a backup.