I just ran into this issue. Non of the answers here happened to solve this for me.
Ended up being nuget packages I added on a branch that, once switched back to master branch, seemed to not exist. Once I did a merge it would say newtonsoft...xml could not stat. I would go to the file in question and open it but Windows threw an error back saying it can't find the file (even though I was looking right at it)
How I solved this was right click delete the file (which worked but I couldnt open it because windows couldnt find it???) and try to merge again and it solved the problem.
Very strange.
Hope this helps someone later.
