This post shows you how to solve the problem
error MSB3821: Couldn't process file x.resx due to its being in the Internet or Restricted zone or having the mark of the web on the file. Remove the mark of the web if you want to process these files.
When rebuilding your project in the visual studio.
To fix the problem above you should go to the x.resx file in your Windows File Explorer, the right-click and select properties. At the bottom of the the dialog is an "unblock" option you should check this and click Apply.