Plesk operations fail with an error: Add Protected Directory failed: columns siteId, path are not unique

Symptoms

Domain/subdomain/customer creation or migration fails with an similar errors: 

PLESK_ERROR: Error: ProtDir_IIS::update() failed: Add Protected Directory failed: columns siteId, path are not unique

PLESK_ERROR: Error: ProtDir_IIS::update() failed: Add Protected Directory failed: Filename: Error: Cannot add duplicate collection entry of type 'add' with unique key attribute 'path' set to '/plesk-stat'

Cause

The database of protected directories has not been synchronized properly with Plesk.

Resolution

1. Remove the failed domain via Plesk > Domains > example.com > Remove.

2. Connect to the server via RDP.

3. Synchronize the database of protected directories by executing the following command in cmd.exe:

   C:\> "%plesk_cli%\\repair.exe" --synchronize-protected-directories-storage

4. Go to Windows Start > All Programs and open Internet Information Service (IIS) Manager:

   • Go to the IIS > Sites tab and remove the example.com website.

   • Go to the IIS > Application Pools tab and remove the application pool of example.com, if it exists.

5. Go to Windows Start > All Programs and open MailEnable:

   • Go to MailEnable > Messaging Manager > Post Offices and remove example.com, if it exists.

6. Re-create business object or re-run migration.