tested with Skyrim v1.8.151.0.7

i noticed something by making a complete system backup.
skyrim loads loose files only if their archive-file-attribute is set.


note for mod user
any decent backup software clears the archive-attribute, so:
if your mod got broken by your backup software, go to your skyrim folder and right click the data folder

• Properties -> Advanced ->
  
• do only if "Folder is ready for archiving" is already checked
  -> uncheck "Folder is ready for archiving" -> Ok -> Apply -> Apply changes to this folder only -> Ok -> Advanced ->
  
• check "Folder is ready for archiving" -> Ok -> Ok -> Apply changes to this folder, subfolders and files -> Ok

note for mod maker
any decent file archiver (WinZip,WinRar,7-Zip,...) saves and restores file-attributes.
so make sure the archive-file-attribute is set before packing your mod.

Has this been verified?

It makes no sense for Skyrim to rely on an arbitrary filesystem-metadata file flag when deciding whether or not to load files. Though I say that after Bethesda used timestamp to set load order for their games previously...

Good to know. This might deserve to be pinned.

Not buying this one, that would mean they made a deliberate change with Patch 1.8 that wasn't present in any previous version for no apparent reason. The chances of them going out of their way to make such a change without a very good reason are pretty slim.

Tested removing the flag for Data/Interface/favoritesmenu.swf, it was still loaded.

OP did you actually test this, I think it's a coincidence

hmm, maybe its os dependant
i'm using Windows XP x64 SP2