RH2020 will not upgrade 1 of my 15 help files
I have 15 help files to upgrade. I got to my last help file for upgrading to RH2020 and RH will not upgrade it. It works fine in RH2019. The message I get is

If I Restart RH and try again, I keep getting the same error. The only thing different with this help file from the rest of them is that the project was renamed in RH2019. However RH2019 handled it flawlessly. Does anyone have any ideas why this one may not be working? This help files does require frequent updates, so I would hate to go back to RH2019 (yet again) for one help file. I have kept all the RH2019 files so I can go back.
thank you to anyone that responds.
