We’ve recently switched to 4.9. One of our developers has created a new C++ project and submitted all auto-generated files to source control (Subversion).
After checking out the project (in TortoiseSVN, not Unreal lingo), I wanted to create some new input mappings. So I opened the ProjectSettings and switched to the Input category.
What happened next was that the project idled for a while, attempting to load (or create?) the settings file. I waited about 10 minutes before I gave up. When I checked the Config folder, I noticed that no DefaultInput.ini existed, so I copied an existing file from another project into the Config folder. After that, I was able to access and edit the input settings.
Later in a reproduction attempt, I tried creating my own C++ project locally. As before, the DefaultInput.ini didn’t exist initially. However, this time as soon as I picked the Input category in the ProjectSettings, the file was immediately autocreated.
As far as I can tell, the only difference was that I hadn’t created the former project myself and that it was connected via Source Control. A co-worker also tried changing the input settings and experienced the same problem.