When I open Lighroom I immediately get an error message that pops up that says 'Lightroom encountered an error when reading from its preview cache and needs to quit. Lightroom will attempt to fix this problem the next time it launches.' When you click ok the box goes away and windows attempts to fix the problem. Then I get a second error box that days the programme has stopped working and windows will notify me if a solution is available. I have tried restarting and updating the computer. I have checked that I have the most up-to-date Lightroom (version 5.7.1). I don't want to uninstall to redownload the software as I have 'work in progress' that I haven't exported yet.
Delete the Preview Cache folder. It is in the same folder the catalog is in. Usually in your UserName folder.