All the sudden, when going into the editor, I get a Map Check error. I have not done anything to the default map, have been working on other things. Now it get’s an AbstractNavData warning. Searched docs and ue4 sites, find nothing.
Can not upload the image of it… so what is says is:
AbstractNavData /Game/Maps/Menus.Mens:PersistentLevel.AbstractNavData-Default: Externally referenced.
what is this?
Sometimes if I resave the map it goes away for a bit, but eventually comes back.
It’s a well known bug, has been subject of other questions already, e.g. check this thread out:
UE4.6.1 “Externally Referenced” on basic map
Hope this helped!
Seems like a hackish fix. Would prefer we know the real reason or that Epic fixes it. That was 4.6.1, I am using 4.9.1… did they just forget about it?
Actually: I am having this issue too with 4.9, and yes, it is hackish, but i guess it is all we can do until Epic fixes it 
But hey, it works!
Also make sure to mark the answer that worked for you as accepted so other people don’t stumble across the thread trying to help too (when your problem is already resolved). Ty and cheers
I do not have an answer, not a non-hackish workaround. I would like Epic to address this so people do not have to jump through hoops and rename stuff because of a strange bug.
Actually Epic has already addressed this, more than once.
Can I do anything more to help you or are you waiting for someone of the Epic staff to post the same thing they already posted in other threads but this time specifically for you? Developers are also just humans, until they find a solution at least there is a workaround. Just try to be patient…
They gave a hack workaround. I will wait for them to actually fix the problem.
Now I am getting this when trying to save a blueprint:
Can’t save …/…/…/…/…/…/Users/Arbo/Documents/Unreal Projects/LearnBP 4.9/Content/GUI/Menus/MM_Settings.uasset: Graph is linked to private object(s) in an external package.
External Object(s):
/Engine/Transient
Guessing this is probably related. Kinda puts a halt on work if you can’t save things… Epic??