Delete VS workspaces for other users

Occasionally a developer leaves a project without deleting their Visual Studio workspaces. It doesn't help to delete the machine and generate a new one with the same name - you will still get this error message when trying to map a local folder:

The working folder K:\AosService\PackagesLocalDirectory is already in use by the workspace [WORKSPACENAME];[Username] on computer [COMPUTERNAME].

If the username presented is not your own name, the workspace is owned by another developer. To view all TFS workspaces use this command in a Visual Studio command prompt:

tf workspaces /owner:*

You see the workspace mentioned in your error message - but how to delete it?
You will need to run the workspaces command with a different output to get the information you need:

tf workspaces /owner:* format:xml

You now get an xml containing all workspaces but with extended information. You will need to find the workspace in your error and note the ownerid value.

<Workspace computer="COMPNAME" islocal="true" name="COMPNAME" ownerdisp="Username" 
ownerid="8e414ake-d6e8-4d74-98c6-d3876cd2b259user.name@company.com"
 ownertype="Microsoft.IdentityModel.Claims.ClaimsIdentity" owner="aydfh7b0-c3b6-6c25-b2c1-d1chn77fead1" owneruniq="aydfh7b0-c3b6-6c25-b2c1-d1chn77fead1">
    <Comment />
    <LastAccessDate>2021-11-23T14:07:24.157+00:00</LastAccessDate>
    <OwnerAliases>
      <string>8e414ake-d6e8-4d74-98c6-d3876cd2b259user.name@company.com</string>
      <string>user.name@company.com</string>
      <string>Username</string>
    </OwnerAliases>
  </Workspace>
  <Workspace computer="mgie10032-1" islocal="true" name="mgie10032-5" ownerdisp="Some Admin" ownerid="8e32gse-d6e1-4d13-98c8-d387694f48asome.admin@company.com" ownertype="Microsoft.IdentityModel.Claims.ClaimsIdentity" owner="353aa275-dff5-6b21-8662-d561d7876cda" owneruniq="353aa275-dff5-6b21-8662-d561d7876cda">
    <Comment />
    <Folders>
      <WorkingFolder local="C:UsersAdmin65c631f1f2SourceWorkspacesProjectname" item="$/Projectname/Trunk/Dev/Metadata" />
    </Folders>
    <LastAccessDate>2021-09-21T06:36:00.58+00:00</LastAccessDate>
    <OwnerAliases>
      <string>88e32gse-d6e1-4d13-98c8-d387694f48asome.admin@company.com</string>
      <string>some.admin@company.com</string>
      <string>some.admin@company.com</string>
    </OwnerAliases>
  </Workspace>

Providing you have Administer workspaces permission you can delete the workspace using this command:

tf workspace /delete [WORKSPACE];[OWNERID] /collection:[COLLECTION]