Converted project won't open (4.7 - 4.8)

I have a Blueprint only project that loads and runs perfectly fine in 4.7.6, but when I convert it to 4.8.0 it will not open at all. The editor splash screen opens and progress is shown. Every time it gets to 45%, it just closes. No crash report, not error message, nothing. I’ve tried opening the original project and converting in place and cloning it. I’ve also manually cloned the project and tried converting that one. No dice any of these ways.

How can I debug this and determine how to fix it? I’ve searched around AnswerHub, but not found anything that fits my situation. Any help would be appreciated.

Using advice I got from the Unreal Engine 4 Developers Community Facebook group, I discovered it seems to be an issue with the DefaultDeviceProfiles.ini file. The only thing in there was some BaseName settings that were empty. Removed those and it launched just fine. I’ll make sure to report this to Epic since that doesn’t seem like something that should cause such a horrible issue.

FYI, for others having similar issues, the advice was to remove all content from the ‘Content’ folder in the project. I just moved it to a folder on the same drive and tried launching. For me, it still had the same issue, but using the same idea I removed the ‘Config’ folder at the same level as the ‘Content’ folder and it worked. So, replacing each file one at a time found where the issue was. The .ini file had only 2 settings in it so it was easy to find what the issue actually was. More complicated projects will probably take a lot more time. I was lucky it happened with a simple project and was the first file in the list. YMMV.