I found that in Quartus 18.1 global libraries list is cleared when new project is created. I reproduced this both on Linux and Windows.
- Add folder to global libraries list in Tools > Options... > General > Libraries.
- Create new project.
- Open Tools > Options... > General > Libraries and observe that added folder to the global libraries list is gone and list is empty.
- FPGA Design Tools
Thanks for the details & it seems to be bug.
I will try to report it till then you can save the .bsf file or library in Quartus installation directory & it will available to all projects like below,
Quartus installation directory/quartus/libraries