DAO large query lockup on Win7 multicore

I have a C++ app that uses a Jet database through D开发者_运维问答AO. Large queries work well up through Vista but lockup under Win7 on a multicore machine. I have tried both jet 3.5 and 4.0. Both fail. I have tried disabling threads in calling prog (my app) - still fails.

Calling SetProcessAffinityMask(1<<GetCurrentProcessorNumber()) is a rather brute-force way of restricting yourself to the current core only. But it's of course better to use a debugger to determine why it locks up. Which two threads deadlock?