What is the "storage.ide" file beneath my Visual Studio solution folder, and what is "persistent storage"?

Everything in the .vs folder should be excluded from your source repository. It is a folder created by Visual Studio for storing user specific information. Previously there was a .suo file which held this data.The change came from a UserVoice suggestion.

Additionally, there's a very useful GitHub repo that has common .gitignore files for various project types and you will see that the Visual Studio version completely excludes this folder too.

Even after adding the .vs folder like the answer correctly suggested, I still had issues with the storage.ide being in my branch and not being able to switch. I tried clearing the git cache like this answer suggested, but it was still blocking me switching branches.

I soon realised though that I was the one being stupid and I had VS2015 and VS2017 open with the same project (and obviously same repo) and 2017 was blocking the storage.ide file.

Closing 2015 and ignoring the storage.ide file in VS2017 sorted this issue.

Hope this might help others..