end_request: I/O error, dev sr0, sector 537392
If you’re getting a similar error filling your screen once you’ve installed Ubuntu, don’t panic. It’s pretty common which is basically because Ubuntu (or any other Linux distro) can’t control your CD/DVD drive properly, it’s probably trying to open/close it but doesn’t know if it has or not. The problem is that you don’t get to see what Ubuntu wrote before because it’s filled your screen up with this error.
If you’ve just installed Ubuntu this probably happened when it wanted you to take the disc out and close the cd tray (if there is one) then hit Enter to finish the installation, so just do that and ignore this error.