Will this also work on 5.2.1? We had the exact same thing happen except we went from 3.7.1 to 5.2.1, on AIX 5.1. Our workaround has just been to stop the thread and copy the current .idx and .msg files to a temp filename, then start the thread. We can then access the records through smat without the lock issue, and it has been simple enough to do that I never persued a fix.