Have the similar issue under lubuntu 16.04. Virtualbox 5.20. i5 GTX 960 Freez in firefox/libreoffice/chromium.. It helps to switch terminals CtrlAlt-F1 and back CtrlAlt-F7
Usaly I killall firefox from CtrlAlt-F1 (terminal alway works) But today I have just switched to new terminal and back and it helps. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1587730 Title: graphic system freezes after a while, can still ssh into machine To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1587730/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs