A number of recent problems that users have reported can be tracked down to using incorrect versions of PowerShell. Tobias Weltner (of PowerShell Plus fame) blogged the details of issue and want you need to do to ensure you are running the right copies. The blog title is Are you using the correct PowerShell version? You should definitely check this out.
Experiment! Enjoy! Engage!
Jeffrey Snover [MSFT]
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