Windows 2008 R2 server
Has ZCM 11.2 MU2 on it with just ZPM and Bundle Manager on it.

I have a simple bundle with a Launch Action Set of:
Launch Executable:
command: c:\windows\system32\msiexec.exe
parameters: /x{GUID}

Success Codes: *

I have it assigned to the DEVICE on Recurring: Device Refresh

If I have the action set to run as Dynamic Administrator, I get an error with the BundleManager stating:
Error launching "C:\Windows\system32\msiexec.exe /X{BIGHAIRYGUID}". Windows error: The directory name is invalid

(obviously msiexec.exe is a LOCAL program--nothing being accessed via UNC path here).

If I set it to run as System, then the bundle doesn't even run at all.

Obviously I cannot use "logged in user".

What gives?

Can you not uninstall existing software on a device via ZCM in an "unattended" state? (is this something with MSIEXEC that I'm not aware of?)