If you use PrimalScript and the PowerShell Community Extensions, you may have experienced a conflict between the two, especially if you are using the default PSCX profile. Thanks to PowerShell MVP Oisin Grehan for pointing out a fix:
Look for the line in your Pscx installed $profile that says:
Start-TabExpansion
and comment it out with a #. This will workaround the problem.
– Oisin
Thanks also to Wes Stahler for bringing this back to our attention: FatBeard’s Adventures in PowerShell: Resolved! Conflict between PrimalScript and PSCX