Unable to access Plesk: Warning: Unknown: failed to open stream: No such file or directory in Unknown on line 0

Symptoms

Unable to access Plesk:

Warning: Unknown: failed to open stream: No such file or directory in Unknown on line 0
Fatal error: Unknown: Failed opening required 'auth.php' (include_path='.;C:\\php\\pear') in Unknown on line 0

or

Warning: Unknown: failed to open stream: No such file or directory in Unknown on line 0
Fatal error: Unknown: Failed opening required 'auth.php' (include_path='.:') in Unknown on line 0

The following command didn't resolve the issue:

C:\> "%plesk_bin%"\ai.exe --select-product-id panel --select-release-current --reinstall-patch --install-component base

Cause

Failed upgrade, not all packages were upgraded.

The provided command is not applicable to Plesk Onyx.

Resolution

1. Log into the server .

2. Complete Plesk upgrade:

On Windows

C:\> "%plesk_bin%\\ai.exe" --console

Or

C:\> "%plesk_bin%"\ai.exe --select-release-current --reinstall-patch --upgrade-installed-components

On Linux:

# /usr/local/psa/admin/bin/autoinstaller