Is there a way to remove unknown users from page watching?

[Jonathan Simonoff]

We use LDAP to manage our users.  When someone leaves the company, and thus disappears from LDAP, anything they did in Confluence ends up looking like "Unknown User (theirOldID) (theirOldID)".  This shows for pages they were watching.

I can't remove these unknown users' watches – when I try, it appears to work, but when I go back to Manage Watchers, the unknown user is still there.

Another sympton is that  when I try to use getWatchers from the xml/rpc API, it gets a null pointer exception for pages with unknown users watching, and doesn't return any watchers.  (I realize xml/rpc is deprecated, but I don't see a way to do this with REST.)

We're using 5.5.

[Guilherme Nedel [Atlassian] · Accepted solution]

Hello Jonathan, the recommended route do disable users is to first perform that through Confluence UI in the Deactivating Users admin section. There in an improvement request for an admin to perform such trough the interface, filed under https://jira.atlassian.com/browse/CONF-22313 though currently that would only be possible through DB queries, for that backup your DB first, and use the following: 

DELETE FROM notifications WHERE username IN (SELECT user_key FROM user_mapping WHERE username= '<user's name>');

Source: https://confluence.atlassian.com/display/CONFKB/Removing+Watches+for+a+Deleted+User

[Michelle Vincent]

This still does not work if they are an unknown user. If I remove them from a page or space watch, and close the list, when I reopen, the unknown user is back. This is in 5.9.5 and 5.10. 

We tried the database query mentioned by Guilherme, but now, the space where I know this particular "unknown user" was a space watcher, will no longer load the watchers in that space. It gives a spinning wheel of death. 

Is there a ticket open with this problem?