“GatherAllFilesToPublish” Error in VS2010 Project Upgraded to VS2012

PROBLEM: After upgrading a VS2010 web forms project to VS2012, when I went to publish the project I received this error "The target "GatherAllFilesToPublish" does not exist in the project.".

SOLUTION: For me I simply unloaded the project, edited the project file to change this line:

<Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v10.0\WebApplications\Microsoft.WebApplication.targets" Condition="false" />

to this:

<Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v11.0\WebApplications\Microsoft.WebApplication.targets" Condition="false" />

After saving and reloading the project file the upgrade wizard automagically kicked in and did some magic and the publish started working.  

Aftewards I went in and had a look at the project file again and it seemed the upgrade wizard added a PropertyGroup element with VisualStudioVersion and VSToolsParth sub-elements (similar to what this guy recommended manually adding but for me manually adding them didn't work - <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v10.0\WebApplications\Microsoft.WebApplication.targets" Condition="false" />)

You'll also find lots of links about renaming Microsoft.WebApplication.targets and running a repair (http://stackoverflow.com/questions/10989051/why-do-i-get-the-error-the-target-gatherallfilestopublish-does-not-exist) - which I tried but this didn't fix the issue.

Cannot merge branches due to "incompatible pending change" error

PROBLEM: Merging two branches in TFS2012 and it fails saying there are 0 errors but X warnings - refer to Output window for details. When you check the Output window you see:

"TF203015: The item $/XXX/YYY has an incompatible pending change"

SOLUTION: In my case, it was because the file in the changeset I wanted to merge (web.config) had pending changes in the target branch which had been added to "Excluded Changes".  In my case I moved the file to "Included Changes" and Checked In the changeset (so the server knew). Then I was able to merge my two branches.  I think if I had discarded my changes on the target branch for that file it would have potentially resulted in the same effect.  Some other googling showed that sometimes people had this issue due to file permissions but that wasn't the issue in my case. That's a few hours of my life I'll never get back!