Comments

• ChrisIceBox

  July 2016

  I believe it's mainly for caching, but don't hold me to it.
  
• hedgefield

  July 2016 edited July 2016

  it's not essential for your project to have the Library folder - if you use version control to sync the project to different computers you (should) never include it, so it seems to regenerate it on the fly on each machine, as Chris said, some kind of caching. But I wouldn't delete it just to get some free space, some weird things might happen.

  
  

  And ESPECIALLY DO NOT delete the metadata files, those store all the inspector settings for your assets.
• Alverik

  July 2016 edited July 2016

  Ever wondered why you can "re-import" an asset, with a single click, and get a default, original copy right back? Basically, every time you import something Unity takes it, and compresses it (depending on your settings) then puts it in the library folder to use (probably converted into an internal format). 

  
  

  You don't actually work directly on the files in the Asset folder. The actual assets you are working on with "live" are the ones stored on the library. Unity doesn't even update prefab's original files until you save your scene or project (or close, which I think saves projects settings too). This is great on one side, because you can always go back to "factory defaults" versions of your assets, at anytime, in case of a mishap, but it also means your project is holding every asset twice... put a 150MB package and you'll see about 300MB of usage in you project. Painful but necessary, I guess. 

  
  

  Now, as Hedgefield said, for sharing your project the library folder is not necessary, because if its not there Unity automatically regenerates it. Problem is, if your project is immense, the regeneration of the library folder might take ages! I have a project I use to browse my "library" with nothing but props and environmental assets I've collected. It's a 32GB project (about 16GB of real stuff). Once, because I wanted to restructure my folder hierarchy, I made the mistake of deleting everything but the assets folder, "to start fresh". And, oh boy, I regretted it. It took my PC about a whole day (15h-20h) to auto generate everything again. So, if your project is very big I don't recommend you to delete the library folder, unless you have the time for waiting...
• joesan

  July 2016

  Thank you both, but it doesn't make me happy to keep 23000 files for every project I have. I am not a professional gamer and have made just 6 projects that means 4 x 6 = 24GB. Sure nowadays with 1 and 2GB discs it's nothing.

  Well I'll live with it. and thanks again  
• joesan

  July 2016

  of course above I meant 1 and 2 TB discs not GB....... I come from the times when I had to develop a system software with 8KB memory cards only !!!
• Alverik

  July 2016

  Well, if they're completed projects and you won't be compiling them again in the foreseeable future, I don't see why you can't just go ahead and delete the library folders. I just don't recommend you to do it for your active/WIP projects, as that may be more troublesome than helpful...
• Satsuma

  April 2021

  Um so my metadata inside the project library folder got currupt somehow when my computer blue screened unity was not open and when I go to open my project after blue screen it wants to reimport everything 2018.4.8 version pls tell me
• ChrisIceBox

  April 2021 edited April 2021

  @Satsuma As this is a Unity issue, you'll be best off asking on the Unity forums.

  In my opinion though, probably best to back up your project and let Unity do what it wants to.