If the GUI freezes but the cursor still moves then it's the gnome-shell process that's frozen while Xorg is not frozen. Although gnome-shell may become frozen by kernel or hardware problems, not just its own bugs.
Next time the problem happens, please:
1. Wait 10 seconds.
2. Reboot.
3. Run:
journalctl -b-1 > prevboot.txt lspci -k > lspci.txt
4. Attach the resulting text files here.
5. Check for crashes using these instructions: https://wiki.ubuntu.com/Bugs/Responses#Missing_a_crash_report_or_having_a_.crash_attachment
If the GUI freezes but the cursor still moves then it's the gnome-shell process that's frozen while Xorg is not frozen. Although gnome-shell may become frozen by kernel or hardware problems, not just its own bugs.
Next time the problem happens, please:
1. Wait 10 seconds.
2. Reboot.
3. Run:
journalctl -b-1 > prevboot.txt
lspci -k > lspci.txt
4. Attach the resulting text files here.
5. Check for crashes using these instructions: https:/ /wiki.ubuntu. com/Bugs/ Responses# Missing_ a_crash_ report_ or_having_ a_.crash_ attachment