This is more of a reminder for me than anything. In VS2015, when you’re pulling a branch from source control for the first time – a perfectly working application may suddenly throw thousands of errors and die in Shakespearean style. Every last gasp, or error message, will seemingly come from the fact that System.Object or similarly ubiquitous type is missing a reference.
The answer for this is simple, as long as you ignore all the errors and instead look at the project. For some reason when I added my solution to TFS Online, it did NOT include the project.json files in the initial change set. When I pulled the code onto a new machine, this missing file destroyed any change I had of building the solution. Find the file in your original build, add it, sync it, pull it.