1 - Reinstall - Hit Windows key and type 2018 Lacerte Web Setup - Hit Enter to start the install.
2 - If that fails use the FORCE install outlined here https://proconnect.intuit.com/community/help-articles/help/how-to-perform-a-force-install-of-lacerte...
NO clients show?
Press F10 and look at system file path, option path, Data path. Are they all consistent?
Try Client > Refresh
Do you have a good back up to restore from? If not, be sure you do in the future.
CLPACK is probably what support will try next https://proconnect.intuit.com/community/help-articles/help/clpack-running-the-lacerte-client-databas...
I just did the update and it went fine. I feel the pain of what you are going through, good luck.
"First method didn't work. Will try the force install. What is the chance that my clients will be lost if I do that?"
Zero. The program is separate from the data base. But you have backups you can restore, right?
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