For the last few months I’ve been working on a map (in the editor, not an external program), but somehow I broke it while working on it. When the umap file is loaded, all that happens is I get a message saying that the .umap appears to be an asset file. I tried loading old versions of the .umap from the Autosave folder, but these files wouldn’t load either. What can I do to fix this or recover an old version?
Thanks!
I see its been 24 days since you posted this with no response, which to be is extremely worrisome for this engine.
These are ‘features’ of the engine, that IF aren’t working we should know about it, assuming anyone ‘cares’.
I may need to look at other engines if this is how important requests are handled.
My concerns haven’t been entirely avoided by concerns of messages going unanswered for so long, but having said that, mine was a ‘odd’ issues that I fixed: see other post on this topic.
Usually I get responses pretty fast, but several times I’ve had really strange problems and nobody has a solution. I posted this question on Answerhub and got a reply but no final answer.
After trying some more to repair the file I decided to restart the map, making a duplicate file every hour or so just in case this happens again.
I haven’t seen posts about this problem anywhere else on the forums or answerhub, so I’m pretty sure the issue is extremely rare.
In general support for UE4 is great, I don’t think another game engine would have better support if something like this happened to your project.
Its just worrisome when these things occur, to find out its a well known issue , binary form, and we have no answers.
It doesn’t necessarily inspire confidence 
BUT, after working for a longtime here , and no idea really why, I did get it fixed and the solution was what I"d remembered.
The editor is supposed to warn you , when you’re trying to open a file not compatible with current engine, but it seems it doesn’t always.
It finally did, I make a copy ( safety first) and it make it through.
What a relief, which I guess explains the weird ’ not a umap file, prob. a uasset’ error I guess…