Another blog post about my struggles with weird compilation errors of universal app solution.

MdilXapCompile code 1004 - error windows cropped

This one occurs only when you’re compiling in Release configuration, otherwise it’s not bothering you. I couldn’t find any solution online (at that time) and we were helpless for about a week. Finally we overcame this issue, when my boss stumbled upon, totally by coincidence, on one of his subscribed feeds (or forums or something else) on a thread with similar description and gave me the solution.

What I had to do, was to remove all the resources files from the packages (nuget packages) folder in the solution. I searched them by the resources phrase and literally selected all the files that were ending with resources and deleted them

Resource files in packages folder - important part cropped

After deleting all the resources (I advice no to use shfit + del, but just del, so that in case of deleting something important you can recover it from the bin) problem was gone, and I was able to compile in Release mode again.

Some links, that might be useful on this matter, after quick googling:

Deploying to Windows Phone fails when using Release build

RateMyApp 1.2.4 alpha prevents Windows Phone Universal App from being deployed to device when compiled in Release