Help! Can’t select game instance in project settings, it just selects none every time

Hi I am developing a VR online multiplayer game and I am currently following this tutorial made by Epic games https://docs.unrealengine.com/latest/INT/Videos/PLZlv_N0_O1gYqSlbGQVKsRg6fpxWndZqZ/abmzWUWxy1U/index.html I have created a game instance in my project but when I go into the project settings and go to maps and modes and scroll down to the game instance setting to select which game instance I would like to use, when I click on the drop down box and click on my custom made game instance, the engine simply just resets the game instance to “none” again.
I have tried making a new game instances 3 times in a row and I have tried closing the editor as well and restarting my PC and I have tried clicking the + icon by the game instance drop down box in project settings which created a new game instance and selected it and so I put my blueprint in its event graph but when I saved all my work and closed the editor and reopened my project and went to project settings and scrolled down to check if my game instance was saved, it reset back to none and when I clicked on the drop down box the select my game instance it just selected none and did not want to select the game instance I clicked on. I have also tried launching my game from the epic games launcher as well this did not work either. Please note that the project I am currently working on was not originally made on the PC I am working on it with. It was made on a different PC and I copied it over to the current PC with a 16gb USB stick.
Please can someone help me as I can’t continue on with my project until this is fixed as without my game instance working I can’t have my main menu widget being displayed in my HTC Vive headset.

Thank you in advance.

Make sure your ini file in the Config folder is writable and that you dont have any Software Blocking the Editing (Anti Virus etc.). In Worst case you can edit the .ini by Hand See Screenshoot https://i.imgur.com/PNNmtkH.png