1. Verify that application is not running:
End Process of the application through the Task Manager. Press "Control+Alt+Delete" keys simultaneously then choose "Task Manager".
In the tab called "Processes" make sure Capture One is not running, if it is, then hight light CaptureOne.exe and click "end process"
2. In order to access local settings. Hidden Folders on Vista, Windows 7, Windows 8 and Windows 10 must be accessible.
Go to Control Panel > Appearance and Settings > Folder Options
Select the View Tab from the pop up menu
Select "Show Hiden Files, Folders and Drives"
3. Run the uninstaller:
Open Control Panel > Programs > Programs and Features > Choose Capture One > Right Click > Uninstall
4. Delete this folder:
C:\Program Files\Phase One\Capture One 9 [or 4/5/6/7/8]
5. Delete the Library file: Capture One.col (can be named Capture One.cosessiondb (or .col, .col45, .col50 but delete anyway)
6.Delete the capture one folder lcoated here:
Users > User Name > App Data > Local > Capture One
7. Delete the Preference Files located here:
C:\Users\USER NAME\AppData\Local\Phase_One\CaptureOne.exe_Url....\9.x.x\user.config [or 5.x.x], [or 6.x.x], [or 7.x.x], [or 9.x.x]
There will be sub-folders for every version installed and these contain user.config which contains preferences.