Call of Duty: Modern Warfare Patch Causing Problems

Following the release of a new patch for Call of Duty: Modern Warfare, Infinity Ward tweets a warning to users who get an error prompt about corrupt data (thanks Wccftech). They say not to select either option the message offers, saying you should hard close the application. They say they are still looking into the problem:
We're currently investigating an issue where players are getting an error prompt informing them their data is corrupt or did not download properly. Please do not select either option, but please hard close your application. Thank you for your patience while we work on this issue.

We're still looking into this issue and appreciate your patience. If you are presented with this prompt, please do NOT select any option and hard close your application. We'll provide another update when we have more information. Thank you again for your patience.