When I try to "add Folders" to Lightroom (add folders meaning add photograph files to edit). It get an error that says "Adobe Photoshop Lightroom 64-bit has stopped working. A problem caused the program to stop working correctly. Windows will close the program..." I have plenty of hard drive space. My catalogue is about 85,000 photos now, but deleting photographs didn't seem to make a difference. Please help!
Please make sure to update Lightroom to the latest version 5.71, also attach the crash log from event viewer.
How to check event viewer:Photoshop Elements Editor Help | How to Find Crash Logs on Windows
To add photos to the catalog, you need to "import" not "add folders".
How exactly are you attempting to add the files???