As a general rule, run 2021 Lacerte Web Setup to run a clean install. That will generally work. I try to use this for every update, rather than use the in program update.
Try the new Lacerte Tool Hub https://proconnect.intuit.com/community/help-articles/help/fix-common-problems-and-errors-with-the-l... if you still have problems.
Answers are easy. Questions are hard!
