Just had this happen twice within a week on Win7 64 after uninstalling SP1 RC (I think I had it happen atleast once with that installed as well but can't recall for sure).
I decided to look around and what you know. There's atleast four utilities to save and restore the locations... If this is so uncommon problem that it's not worth fixing *once and for all*, why is there so many utilities from 3rd parties to workaround MS's bugs?
I know there's been attempts to fix this bug atleast in Vista:
one would think that patch is already in 7 (?) and still the problem persists.
In my mind I can see some kind of comic sketch that "explains" the "gruesome details" of saving and loading some coordinates. Having heard some native Windows API stories who knows, maybe it IS rocket science, with multiple coordinates involved and all that?
* eg. by storing several copies of the desktop icon locations and then if some of them magically changes without the user being involved then maybe send a report and offer some Action Center note to ask if user wants to restore the previous icon locations once or every time they magically change.
I think it'd be right to classify this as a data loss/corruption bug, user data, the locations of where I positioned the icons is being lost. Maybe *now* there's the incentive to put some time to fix it.