Are there any free PDF-reader softwares that allow to save and restore the last session? This is possible with, e.g., foxit on windows but not on mac. (I usually work on more than 20 pdfs simultaneously and re-opening all of them every time I have to switch off my mac is very annoying). Thanks for helping me.
If you use Google Chrome as your pdf viewer, change the start-up option, by going to chrome://settings/ to resume and then don't close it before switching off it will resume all of the windows & tabs, including PDF files in approximately the same place when you next start Chrome.
I don't have a Mac so can't be 100% sure on this but it has been that way on Windows for a long time!
I use Preview on my Mac to view and edit pdf's. If I quit Preview with 3 files open, the files reopen when I restart Preview. I don't know if there is a limit on the number of open files for this to work. I don't need to save the session, it just reopens the files that were open when I quit. Screen positions are not reproduced but the files open to the same page as last displayed when shown. Preview comes already installed on Macs.