It is very odd, I added a network drive and can see the files on it. Now I can open some files, but not pdfs. I can open text files and .doc files, but for pdfs I get following error message:
Unable to open document “file:///media/folder/file.pdf”.
Failed to load backend for 'application/pdf': libzstd.so.1: failed to map segment from shared object
I tried copying the file onto my drive and opening it then, same problem. I also tried opening this: http://www.africau.edu/images/default/sample.pdf but it also doesn't work. So I can't open pdfs in general. The strange thing is my collegue also has Ubuntu 20.04 and we both have a fresh default install of Ubuntu and he can open it, but I can't. I didn't change anything regarding the document viewer. How can I open pdfs in Ubuntu 20.04?
I think your default PDF viewer is broken. Please try reinstall evince,qpdfview or somethink like app. On 18.04, they can be installed like: sudo apt install evince qpdfview (no sure if 20.04 is same or not)
Ok, after shortly switching to Windows and then back again, so restarting the computer this works again. I'm still curious how it could happen that such a basic thing as opening pdfs got broken.