It also can be caused due a Virus scanning, I had this issue when accessing files the antivirus first scanned these and only were aviable after the scan, this repetitive each time when accessing a folder. You might try to configure the virus scan not to scan the runtime you have linked with Poser. Also on my first runn with P13 it seemed making a catalog. My Runtime is about 5tb of files over 3'000'000 files in the library I thought that it never stops the scan ! so it also might be that your catalog is corrupted after the scan. But I have no idea where the catalog is saved to remove it .