When you try to upgrade or remove PureMessage for Microsoft Exchange, you receive the error
Error 1603 - 'Error applying transforms. Verify that the specified transform paths are valid'.
This error message refers to a file called 1033.MST.
First seen in PureMessage for Microsoft Exchange
The temp folder has been cleared out sometime in the past, and this has since removed a file called 1033.MST which is mentioned in the registry.
You will need to edit the Windows registry.
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