Lately I have been working on creating my first Team Fortress 2 map with the intended game mode to be King of the Hill, with the help of UEAKCrash's "How to make TF2 Maps" tutorial. I have a whole half of the map created, which also includes blue's spawn point, but now I am having some issues. I had planned to copy this half of the map, then spin it around and attach both sides at the middle. After that I planned to change all the spawn doors and areas on the newly copied half to make that the red side of the map. The problem simply is that I cannot do that. After copying the map, then pasting it, Hammer editor instantly decides to close itself, with no error message. It just simply disappears, then when I reload with the autosave, the new copy has not been made. I have also tried grouping everything together, then copy and pasting it, and that doesn't seem to work either, and the editor simply closes itself again. My question simply is; is this a problem with hammer editor, or my computer not being able to handle the process, and is there a way to fix it so that I can finally move on to finishing my map? If any screenshots are needed, I will provide them. Thank you in advance if you can help!