Welcome back, @TN59.

I appreciate the time and efforts you exerted to fix your issue regarding the out of memory error in the QuickBooks Desktop (QBDT). But don't worry, I want to ensure this issue is taken care of.

First off, you'll want to know that there isn't an option to restore prior updates in QBDT. 

I understand that this may cause your issue with the error. However, I still recommend reaching out to our QuickBooks Support Team again. This way, they can perform an in-depth investigation of this issue and create an investigation ticket if other users are experiencing the same.

As always, feel free to visit our QuickBooks Community help website if you need tips and related articles in the future.

Please touch base with me here for all of your QuickBooks needs, I'm always happy to help. Have a good one and keep safe.