C++ – How to fix the error “Windows SDK version 8.1” was not found

Start debugging, as soon as you've arrived at a breakpoint or used Debug > Break All, use Debug > Windows > Modules. You'll see a list of all the assemblies that are loaded into the process. Locate the one you want to get debug info for. Right-click it and select Symbol Load Information. You'll get a dialog that lists all the directories where it looked for the .pdb file for the assembly. Verify that list against the actual .pdb location. Make sure it doesn't find an old one.

In normal projects, the assembly and its .pdb file should always have been copied by the IDE into the same folder as your .exe, i.e. the bin\Debug folder of your project. Make sure you remove one from the GAC if you've been playing with it.

This warning seems to have been introduced with the new Visual Studio 11 Beta and .NET 4.5, although I suppose it might have been possible before.

First, it really is just a warning. It should not hurt anything if you are just dealing with x86 dependencies. Microsoft is just trying to warn you when you state that your project is compatible with "Any CPU" but you have a dependency on a project or .dll assembly that is either x86 or x64. Because you have an x86 dependency, technically your project is therefore not "Any CPU" compatible. To make the warning go away, you should actually change your project from "Any CPU" to "x86". This is very easy to do, here are the steps.

1. Go to the Build|Configuration Manager menu item.
2. Find your project in the list, under Platform it will say "Any CPU"
3. Select the "Any CPU" option from the drop down and then select <New..>
4. From that dialog, select x86 from the "New Platform" drop down and make sure "Any CPU" is selected in the "Copy settings from" drop down.
5. Hit OK
6. You will want to select x86 for both the Debug and Release configurations.

This will make the warning go away and also state that your assembly or project is now no longer "Any CPU" compatible but now x86 specific. This is also applicable if you are building a 64 bit project that has an x64 dependency; you would just select x64 instead.

One other note, projects can be "Any CPU" compatible usually if they are pure .NET projects. This issue only comes up if you introduce a dependency (3rd party dll or your own C++ managed project) that targets a specific processor architecture.