1 - Try FORCE install https://proconnect.intuit.com/community/help-articles/help/how-to-perform-a-force-install-of-lacerte...

That often cures things.

2. Follow JWolfe in https://proconnect.intuit.com/community/lacerte-discussions/discussion/re-client-stuck-repopulating/... and https://proconnect.intuit.com/community/lacerte-discussions/discussion/pre-filter-on-2019-individual... as he (she) shares what they learned from support

3 CLPACK is Last Resort and you did it already, but try again if 1 or 2 doesn;t do it. https://proconnect.intuit.com/community/help-articles/help/clpack-running-the-lacerte-client-databas...

4. Call support and get them to fix it. Dont' leave the conversation until it is working. https://proconnect.intuit.com/community/help-articles/help/how-to-contact-lacerte-for-help/00/4691 They are just opening now.