Hudson cannot find powershell after update to powershell 3
After a day's worth of hassle we found the answer. We're still not sure exactly why it happened but the powershell directory disappeared from Hudson's path. Then, although PS3 was installed and the machine had been restarted, Hudson for some reason had not picked up the new PATH variable.
Manually shutting down and restarting Hudson finally got it to pick up the correct PATH and fixed the issue.
George:
I had the exact same problem with the Task Scheduler, right after installing PowerShell 3.0. Running simply "powershell" or "powershell.exe" as a Scheduled Task failed. Rebooting the machine fixed it (I couldn't just restart the Task Scheduler on Windows Server 2008 R2).
My guess is what's happening is that after the reboot when installing PS 3.0, the path is set, and by that time all of your automatic services (like Task Scheduler or Hudson) have started.
So let this be a warning to friend and foe alike. When you install PowerShell 3.0, reboot twice!