Unable to rename a system user from a Plesk domain: /usr/sbin/usermod execution failed: usermod: user is currently used by process

Symptoms

The following error message is displayed trying to rename the system user at Plesk > Domain > example.com > Web Hosting Access:

PLESK_ERROR: Unable to execute usermng: usermng: /usr/sbin/usermod execution failed: usermod: user johndoe is currently used by process 31788 usermng: Unable to modify user: johndoe

Cause

Plesk bug #PPPM-10717 which is planned to be fixed in future product updates.

Resolution

As a workaround:

1. Login to Plesk

2. Suspend the subscription under Domains > example.com > Suspend;

3. Disable “PHP Support” on Domains > example.com > Hosting Settings;

4. Stop  “PHP-FPM 7.X” service under Tools & Settings > Service Management;

5. Rename the system user at Domains > example.com > Web Hosting Access;

6. Start “PHP-FPM 7.X” service again at Tools & Settings > Service Management.

Note: Replace PHP-FPM 7.X for the PHP version which the domain is using.