- Plesk for Windows
By default, Plesk creates a system user for every mail account having access to Plesk panel with the same name.
System users corresponding to mail accounts having access to Plesk panel are not removed from the system when the entire subscription is deleted.
#PPPM-9883 "Deleting a subscription with a mail account now deletes the mail account system users."
- Plesk Obsidian (RC1 18.0.15 as #PPP-40082) 04 June 2019 (Windows)
If update is not possible for some reason you may try the following