No idea as to what happened, but due to leaving a partner program I had to uninstall a confidential SDK and completely delete my source build of Unreal Engine, redownload from GitHub and add back what I can still use. This upgraded me to 5.6, so I also had to upgrade the remaining list of platform SDK plugins. Obviously, I can’t say which one in more general areas of the forums, but I don’t think it is relevant as the issue that I ran into during the process of rebuilding things appears to be traceable to the main guts of the engine.
What is happening is that when I go to build the engine (using the Development Editor config), compiling gets almost to the end before failing just three ticks before completion with LNK1181 on UbaHost.lib (which is in the build acceleration component). After several attempts to resolve this from where it left off, I ultimately gave up and started over from scratch… and while doing so, I noticed that the same file hit an issue where it was not resolvable by its reference through normal means during the initial preparation (meaning before all of the other build actions) and that it would take a few minutes for the compiler to run the backup resolution method.
Is there any possibility that the two compiler results are related, and if so then what’s the best fix?
EDIT: The rebuild also failed, with UnrealEditor-UbaController.dll being the holdup from the UbaHost.lib reference.