Whenever you use UNC paths in PowerShell, your script may break. Since a UNC path has no drive letter, PowerShell looks at the current directory instead, and uses the PSProvider attached to the current directory.
So if your current directory is not a file path (but instead the registry drive, for example), your UNC path is interpreted as registry path.
To play safe, always add the correct provider name to UNC paths:
# UNC-Paths have no drive letter # so PowerShell uses the current directory instead to find the PSProvider # for UNC paths, to be safe, always add the provider name manually $exists = Test-Path -Path 'FileSystem::\\server12\fileshare' $exists