Editor Crashes When Laying Track

Pretty simple problem for me, whenever I go to place track down, there's a failure to save popup then the editor crashes. Am I doing anything wrong? I've tried to follow the track laying masterclass faithfully.
Thanks in advance!

 

Have you pressed the save all button before laying the track?

 

You need to ensure the map is saved before doing anything.

 

Ah my mistake! Where is this save all button you speak of?

 

It's just below "Save Current". Or you can just press Ctrl+Shift+S.