Unable to edit some wordpress users

Finally solved a nagging problem in my wordpress test system.   I was unable to edit some test users, not all – some were okay .

Message received was:

Catchable fatal error: Object of class __PHP_Incomplete_Class could not be converted to string in C:\web\wp28\wp\wp-includes\formatting.php on line 405

I had previously worked through another problem with this 9640 patch.  While it fixed another problem, I then started to get this one.  Eventually I found this   http://lists.automattic.com/pipermail/wp-trac/2009-July/053190.html, and  it dawned on me,

Red dawn

Red dawn in Sydney

A test system – plugins not fully uninstalled….Hmm…   In testing amr-users, my user reporting plugin, I have had several plugins installed that create user data, not all of them active now.   I dived into phpmyadmin, deleted any usermeta that related to plugins not in use, and viola – user editing problems fell away