Level maps no longer appearing in UE content browser

I have multipe projects that all keep losing my older maps - they exist in the direcotroy but will no longer appear in the UE content browser . Some have multiple versions and nonone of the versions appear . So I can have a series like namev1, namev2 etc and they all dont appear . What causes this ? Now I’m not even sure how many maps I’ve lost . I have like 13 projects all with different conte each with like 20-100 maps in each one . This is unbelievable that maps will just no longer appear in the content browser cuz you update to a new engine version . How do you get one that doesnt show up to open ? I cant find anyway to load a map that doesnt show up - moving it to another folder doesnt make it load or be seen . This is happening across many of my projects I just am realizing it since version 20 . Any help would be appreciated

i have the same problem,the map does existing in content folders in background, but it doesnt show in th content browse in ue4 opening window.