Plesk Update fails: The installation of the package ‘plesk-repair-module’ failed with code 1603

Symptoms

• Plesk Update fails with the error message:

  Upgrading Plesk repair module...
  Failed to install 'C:ProgramDataPleskInstallercachepoolreleasePLESK-WIN_18.0.20_1215dist-windowsplesk-repair-module.msi': Fatal error during installation. (Error code 1603)
  
  ERROR: The installation of the package 'plesk-repair-module' failed with code 1603. (upgrade: Upgrading Plesk repair module...)

• At the same time, the following messages appears in Event Viewer > Windows Logs > Application:

  Application 'C:WindowsSysWOW64inetsrvw3wp.exe' (pid 42148) cannot be restarted - Application SID does not match Conductor SID.

Cause

Unclear.

Resolution

1. Connect to the Plesk server via RDP. 

2. Start a command prompt as an Administrator.

3. Stop the IIS service:

   Warning: Plesk and websites will be offline while IIS is stopped.

   C:> iisreset /stop

4. Open the folder C:ProgramDataPleskInstallercachepoolrelease and search for plesk-repair-module.msi.

5. Choose the plesk-repair-module.msi file from the oldest Plesk version folder and run it to uninstall the package.

   

6. Start the IIS service:

   C:> iisreset /start

7. Update Plesk with the command:

   C:> plesk installer update