John Robbins has a few tips on collecting minidumps in a blog post. Unfortunately, you typically can’t debug a .NET mindump created on a 64-bit machine by Process Explorer or Task Manager. Satish Arvati describes how to get a 32-bit version of Task Manager launched on a 64-bit machine here, and that solves the problems, but it’s a bit annoying.
Nicely, the SysInternals ProcDump tool gives you a 32-bit minidump by default, or you can ask it to give you a 64-bit minidump. Nicely, you can attach it to the process and have it write a log automatically when the process hangs for 5 seconds, like
C:\>procdump -h hang.exe hungwindow.dmp
It helped me out yesterday.