Unable execute Plesk tools: Access is denied. (Error code 5)

Symptoms

Running any Plesk commands via the command line fails with the error:

Access is denied. (Error code 5) at Unable to connect to pipe

Cause

Incorrect setting of the UAC policies.

Resolution

Set the correct settings in local policies:

1. Connect to the server via RDP

2. Open the local policies using the command gpedit.msc

3. Go to Computer Settings > Windows settings > Security settings > Local policies > Security options

4. Disable two settings below:

   User Account Control: Use Admin Approval Mode for the built-in Administrator account
   User Account Control: Run all administrators in Admin Approval Mode

5. Restart the server to apply changes in local policies