Just like every other game, it is obvious that you will encounter multiple errors and bugs in Call of Duty: Modern Warfare 3. One of these is the Your Data is Corrupt (Reason NIAMEY – LEE) error, which will prevent you from accessing the game, and it is pretty frustrating. There can be multiple reasons behind the appearance of this error, and here is how you can fix it.
MW3 Niamey Logan: How To Fix Your Data is Corrupt Error
At the moment, in order to fix Your Data is Corrupt Error in MW3, you need to press Yes. However, keep in mind that your Loadouts, customization, and certain settings might reset; however, don't worry your rank, unlocks, and purchases will not be lost.
This is an incorrect error as revealed officially by Activision, so it should be fixed soon by them. So, if you don't want anything to get reset, you can wait for an update from the developers.