LrC won't open. When I try to open LrC it said please try an other catalogue but that don't open either.
Your post was moved over from the "Using the Community" forum, which is for getting help using this forum system, to a better forum.
I hope this helps. Best of luck to you.
Please tell us the complete exact word-for-word unedited error message.
The exact words goes in Dutch.
Onverwachte fout bij openen van catalogus.
De catalogus kan niet worden geopend vanwege een onverwachte fout.
If this happens with two different catalogs, then it could be a problem of the preferences or of Lightroom itself. Start by resetting the preferences: https://www.lightroomqueen.com/how-do-i-reset-lightrooms-preferences/