Hi guys?
I´ve just downloaded some files from the forum but when I drag and drop them into the content folder my assets and textures and materials are just som grey balls. and when I put them into the world the assets are just some grey flat things. please help me!
If what you downloaded is in a project you want to migrate them out following this guide
https://docs.unrealengine.com/latest/INT/Engine/Content/Browser/UserGuide/Migrate/index.html
This will keep all materials, textures, nodes etc. intact 99% of the time.
If it was just .uasset files then your out of luck, the .uasset you downloaded is setup for a specific project and to make it “fixed” (the materials in particular) you will have to go and change them by hand 1-by-1. Thats just an issue with binary .uasset files.
TLDR: Migrate it out of a project, if its not in a project, you have to fix it by hand, no way around it, sorry.
Don’t forget to accept an answer that best clears your question up or answers it so when the community finds your question in the future via search/google they know exactly what you did to fix it/get it going as well as keeping answerhub clean so that it gets removed from the “unanswered questions” catagory.
Be sure to mark your question as answered so it goes out of the un-answered catagory and people know the exact answer quickly when they view your post on google/searching. 
well, thanks didn´t know that but anyway thanks.
Nsomnia - how does one “fix it by hand”? I can’t even get the asset to import as it is greyed out. I attempt to import the asset in my content browser by creating a folder, then right clicking on that folder and selecting “import to/game”. My import window pops up, I navigate to the downloaded asset folder and choose “open”, which just opens to a subfolder and so on until I finally get to the .uasset files, which are greyed out and not selectable.