Major Problem - Userman @ 100% CPU

All of a sudden Usermanager is causing my router to sit at 100% usage and will not authenticate clients. System is an RB433AH with an 8gig Compact Flash. Userman database is stored on CF. Running 3.17 with latest bios version. If I disable the usermanager package CPU drops to 1% and the board works fine. This is a major problem as I cannot authenticate users!