[CrashReport] UE4Editor_AssetRegistry!FPackageReader::operator<<() [packagereader.cpp:479]

This is a regular and longstanding crash that has occurred since at least the 4.14 release. The majority of the crashes occur on non-vanilla builds, although there have been a few vanilla crashes.

User Descriptions

• Tried to fiddle around with the example map and importing some assets and blueprints from other projects. Crashed the launcher, and then the launcher crashed again afterwards duing loading (around 72%).
• I was just trying to open a game project I made on november 2016.
• I did Open Level-> And then tried to drag a umap file from another location in WIndows Explorer into the UE Open Level Dialog. (It showed the + so it seemed possible!) It said it couldn't open the .umap (I think it needs to be copied first to the Content dir of project) Ue4 then crashed, and now crashes every time it launches (With this project at least, using Send and Restart button)
• i opened it

Source Context

 479       FArchive& FPackageReader::operator<<( FName& Name )
  480       {
  481       	check(Loader);
  482       
  483       	NAME_INDEX NameIndex;
  484       	FArchive& Ar = *this;
  485       	Ar << NameIndex;
  486       
  487       	if( !NameMap.IsValidIndex(NameIndex) )
  488       	{
  489 ***** 		UE_LOG(LogAssetRegistry, Fatal, TEXT("Bad name index %i/%i"), NameIndex, NameMap.Num() );
  490       	}

repro steps currently unknown