I have a solution that builds fine in VS2015. I just installed VS2017 RTM and after conversion, attempts to build the solution fail immediately with the error:
I ran into the same problem in visual studio 2017, with a large solution that loaded light weight. I looked at :https://developercommunity.visualstudio.com/content/problem/15861/unable-to-build-solution-after-upgrading-to-the-la.html
And they also suggest not to light weight load solution:
a) right click on you solution
b) disable the lightweight loading
c) close the solution
d) reload and recompile the solution.