Ok. Just to let you know, in reference to the larger file 311KB, I am able to OPEN it (in the 2009 pgm) and the system said it had successfully updated the company file to QB Desktop 2021. So, I was surprised when the 6123,0 error msg came up when I tried to open the new file in 2021.  Does that seem odd?

If you think I need to let the File Doctor run longer than 26 hours for the 311KB file, I can. How long do you anticipate that it will run? It's a little misleading because is says when the File Doctor is working, it states...."this could take minutes". A little different if it can takes days, weeks, etc. Thanks for the input. And to confirm, does the file doctor require an internet connection?

I will also complete the File Doctor on the other 6 company files (they range from 30KB-60 KB), thanks.