Ubuntu 18.04 system periodically hard freezing
 

Hi, I'm very new to linux. I've read a lot of the "before posting FAQs" on various forums. I'm attempting to learn how to troubleshoot a system freeze that is periodically happening to me in Ubuntu 18.04 I've recently installed. I did the install that is "bare bones" and not with suggested packages included. I worked a bit with Rstudio (why i installed ubuntu) and had a crashing error that was fixed by turning off GPU rendering option. Naturally, once that fixed the issue with Rstudio crashing, I became suspicious of my GPU drivers so I recently updated them by first running 'apt-get purge nvidia*' in terminal (system froze first time I tried this) and then ran 'sudo ubuntu-drivers autoinstall'. The system still seems to freeze about once every 1-2 hours, typically in an idle period where I go AFK for 5+ min and come back and mouse/keyboard are unresponsive. I've found this Kernel Crash Dump solution tool that seems a bit involved (https://help.ubuntu.com/lts/servergu...rash-dump.html), so I first wanted to ask if the problem can be easily determined from this Logs Application/Important output i've copied and pasted below:

10:15:26 AM bluetoothd: Failed to set mode: Blocked through rfkill (0x12)
10:15:26 AM spice-vdagent: Cannot access vdagent virtio channel /dev/virtio-ports/com.redhat.spice.0
10:15:25 AM pulseaudio: [pulseaudio] backend-ofono.c: Failed to register as a handsfree audio agent with ofono: org.freedesktop.DBus.Error.ServiceUnknown: The name org.ofono was not provided by any .service files
10:15:16 AM bluetoothd: Failed to set mode: Blocked through rfkill (0x12)
10:15:16 AM spice-vdagent: Cannot access vdagent virtio channel /dev/virtio-ports/com.redhat.spice.0
10:15:15 AM hpfax: [1435]: error: Failed to create /var/spool/cups/tmp/.hplip
10:15:11 AM gnome-session-b: Unrecoverable failure in required component org.gnome.Shell.desktop
10:15:10 AM kernel: PKCS#7 signature not signed with a trusted key
10:15:10 AM bluetoothd: Failed to set mode: Blocked through rfkill (0x12)
10:15:10 AM kernel: PKCS#7 signature not signed with a trusted key
10:15:10 AM kernel: Couldn't get size: 0x800000000000000e
10:15:10 AM kernel: MODSIGN: Couldn't get UEFI db list
10:15:10 AM kernel: Couldn't get size: 0x800000000000000e

Thank you for any help!!

Please show us

I had a lot of errors with a freezing system, I couldn't figure out what it was. Then I finally found it was the NVIDIA drivers from the non-free repository.
I had to remove them and install the latest 440 drivers from NVIDIA website.

Once I did this everything worked perfectly.