Have been using LrC 11.4 all last week with no issue. Today Oct 1, updated NVIDIA 517.48, as well as Creative Cloud Desktop and LrC to 11.5. Now LrC won't open. Error msg says catalog file is corrupted and assertion failed. Rolled it back to 11.4 hoping it will resolve issue but still won't open.
You have a backup right? If the catalog is really corrupted, there is a very slim possibility that if you contact Adobe directly, they might offer to repair it, with no guarantees. But the best solution is to go back to your last backup and simply replace that catalog. And ideally, you backup every day!
Author “Color Management for Photographers" & "Photoshop CC Color Management/pluralsight"