I purchased Lightroom and recently updated to 5.6 64 bit and when I attempt to open the application I get an error screen 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." And nothing fixes itself when I try to open it again. I have updated it to the newest version thinking that may help and so far nothing is helping. Suggestions?
IIf you look in the folder where your catalog is located, next to the .lrcat file, you'll find a folder with the same name ending in .lrdata.
Delete the folder, and LR will rebuild it when you restart it.
THe .lrdata folder contains the preview cache, and it can be rebuilt any time. Note that on a Mac this looks like a special file, but the process is the same. Trash it and let LR rebuild the previews.
There are several folders inside the previews folder with the .lrdata which one do I delete? All of them?
DDelete the whole .lrdata folder. LR will recreate it.