目的

A deleted user is shown as Unknown User (username) in Confluence. This KB will provide steps on how to change this appearance. 

 This KB will only be useful when Unknown User (username) is displayed as a result of user deletion (from External Directory side). For missing users after an XML import on please use this documentation instead: User mentions appear as Broken link after XML import

Causes of users appearing as Unknown User

Cause 1 - On Confluence 6.13 and above

• This user has created content in Confluence but has been "Unsynced". More information about unsynced users can be found here Delete or Disable Users.

Cause 2 - On Confluence 6.12 and below

This user has created content in Confluence but has been removed from the external directory side, which may be due to;

• User deletion from the  external directory side
• The user has been excluded from the accounts to be synchronized with Confluence in your external directory
• The external user directory has been removed from Confluence

 As by right Confluence does not allow deletion of this account, users will be appeared as "Unknown User" instead. Quoted form the relevant documentation (Delete or Disable Users - Confluence 6.12 Documentation): You can delete a user from Confluence if they have not yet added or edited any content on the site. Such content includes pages and blog posts, and edits and comments on existing pages.

The reason for the above is that Confluence will still save this user in the database, in order to associate them with the content they had created. This is Confluence's way to ensure that all content in Confluence does not get deleted if a user is disabled. While the user's information and credential do not exist anymore (such as their full name), the association of content creator and this user still exists in the database.

ソリューション

Solution 1 - On Confluence 6.13 and above

Delete the unsynced users to anonymize their username as per mentioned by the documentation: Delete or Disable Users. 

1. In Confluence, go to Administration > User management > Unsynced from directory. 
2. 削除を選択します。

ほかのユーザーへの削除済みアカウントの表示形式について

ユーザー アカウントが削除されると、Confluence 全体 (ページの署名欄、メンション、コメント、ページ履歴など) にわたり、その人物を特定できる情報が匿名化されます。 

• 氏名は "user-38782" などのエイリアスと置き換えられます。
• ユーザー名はユーザー キー (長い文字列) と置き換えられます。 
• プロファイル画像は既定の画像と置き換えられます。 

サイト内で統一されたエイリアスおよびユーザー キーが提供されます。したがって、ユーザーは同じアカウントが作成したページやコメントを特定することはできますが、そのアカウントが誰であるかを確認することはできません。 

Solution 2 - On Confluence 6.12 and below

The only way to change the appearance of Unknown User as a content creator will be to create a new account associated with the old username. Note that this user does not have to be active. As an example, The picture above shows a scenario where a page created by a deleted user which has the username, "jd01".

1. Create a new user with the username "jd01"
2. Set the Full Name field with the name that you would like to see appear in the page (For example: My Company Confluence Admin)
3. After that, all old user's contents (All content that was created by "jd01") will be mapped to this newly created user automatically.
   

Optionally this username can be changed. Please find the documentation to do so: Changing Usernames

In order to make sure that this user is not active, which means to ensure that no one will log in to Confluence as this user, and to make sure that that this user not counted towards the license, you can disable this user. Please find the instructions below

1. Go to Confluence Admin > Users
2. Click on the user in mention
3. Click on disable