Cant update to Sonar v4

Sonarr version (exact version): i was using version 3 but it is now uininstalled
Mono version (if Sonarr is not running on Windows):
OS: Windows 10
Debug logs:
Description of issue: When trying to update to v4 i get the following error:

C:\ProgramData\Sonarr\bin\0Harmony.dll

An error occured while trying to replace the existing file:
DeleteFile failed; code 5.
Access is deined.

Click Retry to try again, Ignore to skip this file (recommended), or Abort to cancel installation.

I have tried to unhide the program data folder, but that didnt work and have looked for people who had similar problems with no luck.

It also just isnt this file, when i try to ignore it happens with several other .dll files

Check in Task Explorer if there is a Sonarr process and/or service running. If so, it doesn’t look like it uninstalled properly. Stop the process/service and try again.