Thank you so much for posting this JD. I have been wrangling this QB issue since Friday morning. You saved many of us a lot of additional pain. Merry Christmas!

Worked for me as well!

THANK YOU! THANK YOU! THANK YOU!

This is the correct answer, thank you!  I'm using VMWARE Fusion and had the same issue.  I uninstalled the latest Windows security update and everything works fine now.  I also hit pause on automatic updates.

Thanks for sharing!  Your fix worked for me ...

OMG!!!!! It works. After days trying to figure this out. Thank you. 

Mr J D Thomas - how do I buy you a beer or send you cookies or something!?! 

THIS is the fix.  No need to downgrade Parallels or uninstall recent Windows updates - changing the Emulation settings on QBD did it. I can't tell you how grateful I am.  I fought with this one all weekend and there was no info and Intuit support wasn't even available.  Installing QBD on a PC laptop and moving the company files over got me going, but this totally fixed it on Parallels VM where I actually want to use it.   I had the same problem as you; couldn't open company file, couldn't open Sample file.  Reinstalled QBD. Did every single thing suggested in File Doctor. Nada.  Monday Intuit support suggest the company file needed repair by them, but then were a bit stumped when I told them I couldn't open a sample file either.  They need this fix posted everywhere!

Again, many thanks for contributing to this community with your knowledge.

Thank you so much for your information, I had the same problem I also realized it was right after an update with parallels and quickbooks ,  so I did as you suggested and downgraded the parallels version to 20 and Quickbooks fired right up thank you so much for posting this is going to hit a lot of people until they get it fixed, I spent 2 hours with support for quickbooks and basically they gave up. lol thanks again 

thanks again this worked for me , I was getting ready to buy a windows computer, spent 2 hours with quickbooks support and they finally gave up. as soon as I downgraded to version 20 my quickbooks fired right up , this is priceless information thanks again 

See Parallels Forums "Quickbooks Desktop no longer working after 26.1.2 upgrade"

https://forum.parallels.com/threads/quickbooks-desktop-no-longer-working-after-26-1-2-upgrade.368876...

that refers to the Parallels Knowledge Base solution "Quickbooks Desktop application not loading"

https://kb.parallels.com/en/131061

which notes two solutions, the first of which that sets compatibility emulation settings to very strict execution has been mentioned in this thread but does not always work (it didn't work for me), while the second of which is to downgrade to Parallels v26.0.1 (which did work for me) and follow the instructions for turning off automatic update.

After I downgraded to the older Parallels version I still needed to restore from backup as I still couldn't run a company file I had earlier tried to restore when things were broken (so it may have created a corrupted company file), but restoring from backup and subsequent run/use of that company file worked and I verified that quitting QuickBooks, shutting down both Windows and Parallels, and starting up again still worked.

So while you can certainly try the simpler possible solution of changing the compatibility emulation settings, if that still doesn't work, then downgrade to Parallels v26.0.1.

Does anyone know if the Parallels update 26.2.0  that recently came out fixes this issue. I am reluctant to do the update until I know more. It has been an expensive nightmare.

Thank you. Your solution to use a previous version of parallels solved my problem too. I just wish I had found it a week ago and not wasted so much time.

I just experienced the same issue (QB on my ARM/Windows under Parallels stopped working).

Patching windows to the latest update and upgrading Parallels to 26.2.1 fixed the issue.

The Parallels 26.2.1 update fixes the problem.

That release does not, but 26.2.1 that just came out does fix the problem.