Login fine, except for one specific user

[ndaniels]

4.2 OS - login works fine for everyone except for one specific user. Username is correct and so is password.
When he tries to log in under IE it says that index.php cannot be found. Under Firefox you get a warning that it's trying to open index.php, but if you save it and look again it is a zero byte file.
User is active, everything in the profile looks correct, etc. He tells me that this happened before and that "someone" twiddled "something" to get him working again.
If you duplicate the user account, the clone works just fine (except, of course, that it doesn't point to all the prior leads, etc....)

Why would Sugar cough up on one specific user? What should I look at/for?

[Angel]

If you duplicate the user account, the clone works just fine (except, of course, that it doesn't point to all the prior leads, etc....)

Try updating that copied user's ID column to match that of the old user name record. You'll need to delete the older one first. That should relink everything for you.