For the last 2 years this has been happening intermittently on a DNN site.

A content editor calls in and says their login was working earlier that day but now they login and do not see any of the site content.  They see the 'blue arrow' and allows them to access the module settings but it doesn't give any module specific links. (ie a Text/HTML module would not have the edit text option but would have the Settings, Move, Import/Export content options).  This is user specific in that anyone not logged in or logged in as a different user does not experience this behaviour, and if I delete a user and recreate them it solves the problem.

Here is what it looks like when you login and are in edit mode, the module int he content pane is a text/html module and has content in it i promise.  Any ideas?