What do you even call this? I was migrating the project from Unreal Engine 5.7 to 5.8, and the project started crashing. I tried everything I could think of and even brought in AI with direct access to all the files.
Eleven hours, seriously! One thing breaks, then another, but most of the time the project simply will not load at all. The engine itself is fine, and every other project works perfectly. Codex had already started disabling engine features, but I stopped it.
As the battle went on, I found some “partisans” hiding in the folders even though Unreal Engine 5.7 no longer showed them. Some were still marked as belonging to engine version 4.x. I removed them manually and checked every folder against what the editor displayed. The project still crashed.
I had already started testing how to rebuild the project from scratch in 5.8 while transferring the algorithms from the working 5.7 project open alongside it. It can be done, but it is slow and difficult: several days of work, followed by who knows how much more time debugging.
Then the thought finally occurred to me: surely the problem could not be in the engine itself. Instead of disabling plugins and engine features, I needed to disable parts of the project. It turned out that I could. Within half an hour, the “partisan” was caught: the startup level. The level itself.
I have no idea what could be wrong with it. It is basic—possibly the most basic level in the entire project. It starts a chain of logic located elsewhere, has a couple of interfaces, a simple sphere with a single light source, and a background. All of that—and far more complicated things—exists in other levels. Why this one?!
I do not know whether to spend more time looking for the cause or rebuild this level from scratch in half an hour—identical, but new. I will most likely build a new one, and the mystery will remain a mystery. It is as if an example in which 2 + 2 had always equalled 4 suddenly developed an error that brought absolutely everything down, while causing no problems at all in the previous engine version.