How to fix Diablo 3 error 3003?

June 4, 2012 - PRLog -- On may 14 Blizzard shut down Diablo 3 servers  for maintenance to fix error 3003 and similar other errors. To solve Diablo 3 error 3003 there were no official updates, however, some maintenance tips were put together by IT community in different forums and web sites.

To fix Diablo 3 error 3003 you should remove Preference File, update DirectX, Update drivers, configure Internet settings, manage background services and remove unwanted temporary files.  

Remove Preference File: First step to fix Diablo 3 error 3003 is to remove D3Prefs.txt file which contains game settings. In some cases wrong values stored in this file causes Diablo 3 to crash. Removing/deleting D3Prefs.txt  is simple--just click on Start > My Documents > Diablo III > D3Prefs.txt  (right click on it and select DELETE)

Update DirectX: Next step to fix Diablo 3 error 3003 is to update DirectX. To run this game updating DirectX is mandatory. You should download latest version of directX from Microsoft’s corporate website.

Check Internet Setting: Dial up Internet settings could cause Diablo III error 3003, dial users should disable Network Connection each time. Open Internet Explorer > Tools > Internet Options > Connections > Dial whenever a network connection is present > apply > OK

Manage background services: Background running applications can conflict with game resulting in diablo 3 error 3003. You may use Microsoft Configuration Utility to disable background running applications.

Finally you should remove unsupported drivers through Device Manager. Also remove temporary junk and optimize your PC for peak performance of games using PC Fresher.

Follow this procedure as well: http://www.slideshare.net/TeraByte57/how-to-fix-diablo-3-...