i did not switched back to 0.16, the library is just empty, like i never had any.

edit: sorry, just checked, i already imported some BP Books into this Libary, cause you know, can't play with out em anymore.
but my old collection might be in there somewhere?

after switching to 0.17.9 is guess, my whole BP library was gone. i noticed it just now at 0.17.14 after making a new save....

is there any way to restore the old file or do i have to start again?
If so, what file do i need to backup manually to avoid such error from striking again.

Cheers