(to restore in case something goes wrong) Now, if the issue was the launcher not patching the Diablo III client because it was using a different patch_url, your client should be patched and you should be good to go.
However, if you play in a region that’s behind your client’s version, you need to revert your client to the previous version.
As thousands struggle to play Diablo 3 and servers buckle under the strain, Blizzard has explained the various error messages players are receiving as they attempt to log-in - and offered advice on how to deal with them.
Two of the more popular error messages are 37 and 12.
Hi,for the past couple of hours I've been trying to get Diablo 3 to launch.
However, everytime I press 'play' on the launcher I get an error screen which reads 'The application encountered an unexpected error'.
We'll keep this post updated throughout the next couple of days with the latest problems and info on how to fix them.
We'll also include non-Blizzard sources when appropriate (but in general, Blizzard is pretty on top of all these).
At this time, Compatibility Mode for the retail tools is no longer needed.Basically, the “new patch” message means your Diablo or dll does not match the version accepted by the server.If different regions are at different versions, you need to set your patch_url to get updates meant for the region you play in.—————– ———- Change the patch_list by editing the .file.—————– This is how you can set your client to get updates whenever they’re released in the Americas region: (Shouldn’t be needed if you use a client meant for the region you play in.) Before you start, make a backup copy of the original .file.I have included the forum post word for word below in blue (you may want to thank the poster “Barthus” in the forums if it does the trick for you), as I said I was getting the patch loop issue and this fixed it for me.I know there’s already a sticky about this, but that method is a little more complicated, will reset if you delete the Agent folder and may also reset during an Update.0# Diablo 3 Known Errors and Issues You can track of other known errors and issues with This Thread.1# ATI 1.24 Catalyst Visual Effects Fix Download and install the latest Catalyst 12.4a driver hotfix if you experience any graphics issues with your ATI card. While you shouldn’t experience any compatibility issues with Diablo 3, running Diablo 3 Tools in Compatibility Mode (XP SP3) may help when all else fails.ATI Radeon HD 4600, 4700, 4800, 5000, 60 series products are unaffected, as is Windows XP.Update: ATI has released a Catalyst 12.4a driver hotfix for the affected cards.