Jeff, I found the problem. The LDM user on ldm.michiganwxsystem.net has this crontab(1) entry: */30 * * * * ~/nawips/cleanup.sh 1>/dev/null 2>/dev/null The script "cleanup.sh" has this command: for semid in `ipcs | grep ldm | cut -f2 -d" "`; do ipcrm -s $semid; done This command deletes the semaphore used by the upstream LDM database feature in version 6.11 to manage concurrent access to the database. Regards, Steve Emmerson Ticket Details =================== Ticket ID: XGQ-958194 Department: Support LDM Priority: Normal Status: Closed