Hi
The map was working fine, but suddenly during the 4th production build the map crashed and whenever i try to open it again it gives me that error and crash the engine… i tried to use backups but they give me the same error
link text
Thanks !
Seems like you got a corrupted cache; Go to your project folder and delete the “Saved” and “Intermediate” Folders (maybe copy the “Saved” folder away, as there are autosaves of your maps etc in there), this should clear the caches and you should be able to build lighting etc again.
Hey thanks for the reply, after trying what u said the issue is still going on
still whenever i try to open the map the engine crashes. even when i use any of the old autosave maps the engine keep doing, something went wrong with that map ( i even tried to copy it to a new project ) manually since even right click on it crashes the engine so i can’t use migrate. still the map crashes the engine
Ok, just had a look at it again; The bad news: This is a known issue with 4.12.5.
The good news: Its already fixed in 4.13.
If for some reason you cannot upgrade to 4.13, then it will get a bit difficult. If you are at least moderate in C++ and git handling, then you could download the sources for 4.12.5, apply this fix yourself (https://github.com/EpicGames/UnrealEngine/commit/bac67b96d7f1d4323db570c6a0485cdfb0414c23) and build the engine from source.
Sorry!
i will go for 4.13 I was avoiding changing engine version till iam done with the project, thanks for the help!
If my answer was helpful, please consider “accepting” it 
6 years later sorry just saw you request 