It sounds like some of the NS subsystem files did not get restored. Was it the system volume set (MPEXL_SYSTEM_VOLUME_SET) that encountered a disk crash? If so you would have needed to do an install from a current SLT, then RESTORE @[log in to unmask], @[log in to unmask] with the OLDDATE, CREATE, and KEEP options. The user community is able to get back on the system because they may be connecting with hardwire DTC connections. DTC's do not require the NS3000 subsystem.