Plesk repair installation launched from Plesk GUI failed: Another instance of bootstrapper is already running. Please\nwait until it finishes

Symptoms

Plesk repair utility launched from Tools & Settings > Diagnose & Repair fails with the following error:

PLESK_ERROR: {"id":1,"cmd":"plesk repair installation -y","type":"failed","message":"Reconfiguring the Plesk installation","level":0,"details":"Another instance of bootstrapper is already running. Please\nwait until it finishes.\nIf you are completely sure there is no other instance running,\njust remove \/var\/lock\/parallels-panel-bootstrapper-running.lock\nfile and retry.\nNote: running more than one instance at once may badly damage\nyour system.\n"}

Cause

Plesk Repair Kit extension bug EXTPLESK-2336.

Resolution

As a workaround, run the repair via CLI:

1. Connect to the server via SSH

2. Launch the repair utility via command-line:

   # plesk repair installation