VDMEnumProcessWOW returns no processes on Vista

Question

I'm trying to use VDMEnumProcessWOW to find all 16 bit host processes on Vista. I call it, and it appears to not find any results even though I do have a 16 bit app running.

I've also tried calling VDMEnumTaskWOWEx with the process id I got for ntvdm.exe from Windows Task Manager, and that also returns no results.

ntvdm.exe has user name joeBlogs, and the application I've written to call VDMEnumProcessWOW is running as a service under the SYSTEM account. Is the problem that I need to have them running in the same session?

EnumProcesses works ok across sessions, but is VDMEnumProcessWOW different, or is there something else I'm missing? The documentation I've seen on this so far is a little sparse.

The VDM does contain the WowExec.exe task that the function's documentation says is required.

Thanks.

Answer 1

Yes, a colleague just answered this. He ran into this problem before. It appears that VDMEnumProcessWOW does not work across sessions.

Also, Vista has some other problem enumerating 16 bit processes (I'm not exactly sure what they symptom is). There's a Microsoft supplied HotFix that is required to make this work.

Answer 2

You can request the hotfix through this link.