Please follow the steps below to get your Perfectly Clear working:
1. Close Historian.
2. Run Windows Explorer.
3. Browse to the folder containing the installed Historian software. This is normally one of the following:
For 32-bit Windows - C:\Program Files\Panstoria\Historian 4
For 64-bit Windows - C:\Program Files (x86)\Panstoria\Historian 4
4. In that folder find the application file named "vcredist_x86" and run it to install missing components.
5. Run Historian. The Perfectly Clear feature should now work.