I have some Windows XP sp2 with NW Client 4.91sp3 systems accessing a Netware 6.0 sp6 server. When they go to some of the folders Windows explorer hangs and stops responding then finally allows access. By default "Hide protected system files (Recommended)" is set in windows explorer. If I un-check the box to allow viewing the the files the fault goes away. These workstations were built with XPsp2 and NWClient 4.91sp3. They were not upgraded to these versions. Older desktops that were originally built with older client versions or have older versions don't have the issue.