Hey there @Rishiwarman! Welcome to the community! The mechanism to add all to the library is currently not functional. They should in fact be yours, adding to the library must be done for now it seems if you want to use the asset before that is corrected.
- After you claim all Megascans , you can access them from the Quixel profile on Fab, but they will not be added to My Library at this time. We’re working on a solution to add all of your claimed assets to My Library as soon as possible.
- UPDATE 10/23: You may now add individual assets to your Fab library; we do not yet have a solution to add them all to your library. If you have claimed all assets, each Megascans listing page will correctly indicate that “You own this item” even if the item does not appear in your library.
per this post: