Unable to use Plesk login command or install/update extensions after interrupted Plesk upgrade: error while loading shared libraries

Symptoms

• plesk login command fails with the following error:

  # plesk login
  /usr/bin/sw-engine: error while loading shared libraries: libaps.so.1: cannot open shared object file: No such file or directory
  exit status 127

• Updating or installing new extensions get stuck in Plesk UI forever.

Cause

Interrupted Plesk upgrade which causes Plesk and system packages to be not fully configured.

Resolution

Note: Steps below are intended only for Debian-based systems.

1. Connect to the server via SSH.

2. Configure all interrupted packages on the system:

   # dpkg --configure -a

3. Continue Plesk upgrade:

   # plesk installer