I've seen some posts about a bug on Lightroom Classic, where we try to open a Catalog that was built with an older version, and when it tries to update the Catalog an error message appears :
after reading your posts and understand what could be wrong, I uninstalled the version 11 and have reinstalled the version 10.4. After this, Lightroom tried to open the Catalog, but another error message appeared:
What can I do more to recover this Catalog (there is a lot of work inside this Catalog and if I can't recover it I'll lost all the work done).
note: this Lightroom is installed on my client's computer.