Hello there! I'm terribly sorry to hear that the map editor for Far Cry 4 causes your game to not launch properly. For starters, please verify the game's files in Steam. Since you just downloaded the editor, this would be good to do as it ensures everything required is properly installed. It will also replace any missing or corrupted game files that could potentially be causing these crashes! Then, you can try running the game as an administrator[support.ubisoft.com] to see if that makes any improvements. Granting games admin rights allows it to have full permission to run as it should on your system, which can ultimately resolve various technical issues -- like crashing. Finally, you can complete the other steps listed in our technical troubleshooting guide[support.ubi.com]. Those steps are simple and quick to complete!

Ultimately, if none of these suggestions help to lessen or resolve the crashing, please upload your MSinfo file[support.ubisoft.com] in a case at support.ubi.com. Our technical team would be more than happy to provide specialized assistance to get this resolved. Please comment your case number below for me once it has been created. Thank you!