I recently discovered a problem with Firefox and phpBB User Administration (at least in 2.0.11). When pulling up any user, you will see this:
Username: * [some static username you've used]
For example, if you've entered "Joe Blow" recently as a username somewhere, then you will ALWAYS see Joe Blow here, regardless of which user you pull up. But all the other user data will be okay, at least I think so (not sure about the password).
Why? It appears the Firefox form filler is inserting data (which makes no sense as this field should not be blank). This can easily foul up your user database if you're not careful. There's no telling what other fields might be getting changed.
Is this a problem with 2.0.11 coding (i.e. not providing unique form fields) or is Firefox being sloppy?
I would have to recommend going to Firefox > Tools > Options > Privacy > Saved Passwords, then doing Clear, and then expanding this option and unticking the "Remember Passwords" checkbox.
I don't know if this has come up before (I'm sure it has), but maybe it will save someone some grief.