Migration finishes with warning/error: Shared IIS application pools are not allowed in the IIS application pool settings

Symptoms

• The following warning and then error message appear on attempt to migrate subscription:

  PLESK_WARN: Shared IIS application pools are not allowed in the IIS application pool settings.
  The following subscriptions are affected by the issue:
  example.com

  PLESK_ERROR: Failed to fix permissions of files for subscription 'example.com' Migration tools tried to perform operation in 3 attempts: Command execution failed on the local server with non-zero exit code.
  command: D:\Plesk\bin\subscription --set-iis-app-pool-settings example.com -iis-app-pool-turned-on false
  exit code: 1
  stdout: 
  stderr: Settings of dedicated IIS application pool are set according to the server-wide performance settings.

• On source and destination server settings is: Tools & Settings > IIS application pool > Global Settings is set to Always assign one application pool to each subscription;

Cause

The issue is caused by Plesk Migrator bug with ID #PMT-4643, which is planned to be fixed in product future updates.

Resolution

Warning/error can be safely ignored if IIS higher than 6 is used on the source server.

If IIS 6 is used, there could be potential problems with file permissions.