UNRESOLVED - Zorin 16 Pro reboots and freezes randomly

Hi -
I've been running Zorin OS Pro since 2019. First 15 and now 16. (NUCi5BEH with 32 GB RAM and dual-booting with Ubuntu 20.04)

Over the last year, I've been plagued with random reboots and freezes. The reboots are self explanatory, the freezes result in the NUC lights showing that the PC is operational, but the monitor never comes out of sleep.

I do not have any of the same issues when I'm in Ubuntu.

If this were a Windows PC, I'd be able to troubleshoot it. However, I have had zero issues in my 5+ years of using a *nix distro and consequently don't know where to start to diagose the issue.

Any suggestions?

(the fact that I have to post this is a testament to the rock-solid nature of the OS!)

There are two things that come to mind:
Zorin OS 16 is using a different kernel than Ubuntu 20.04 is.

RAM. - Have you run Memtest to test the RAM?

For kernel, try adding a grub parameter:

sudo nano /etc/default/grub

Change GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" to:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nvme_core.default_ps_max_latency_us=5500"

Also, you might try disabling power management...

CTRL ALT T to enter terminal.

xset -dpms


Your Tech Support Guru

I have the memtest running right now. Through 3 of 4 passes with zero errors so far.

What does the grub edit suggested do? Asking to learn.

I'll give the power management suggestion a try as well.

Thank you!

It sets the Autonomous Power State Transition to 5500 microseconds, allowing more time for the NVME drive to switch between power save states based on the rules configured in the driver (Or kernel).


All 4 runs of the memtest came back clear
Applied the change to GRUB and problem came back an hour later.

Just applied the disabling the Power Management. Will report back.

1 Like


The disabling of the Power Management seemed to fix it...was working fine for ~5 days.

The last 24 hours have returned to prior state - I return to the computer with the PC's power light but nothing renders other than a black screen.

Just re-ran xset -dpms, as I did an update which I thought might have reverted things back.

Will update again.

1 Like

While I was reading your post, that is exactly what I thought. We had a big update yesterday, and then we had another update today. So the setting could have easily been reverted in the update.


~24 hours later and all is running well.

Will report back after a couple more days

1 Like

I'm at a loss.

The rebooting / black screen happens in spurts. I'm assuming I have not run xset -dpms every time I've received an update, but I'm also not certain if I should need to after every update.

My current tests involve Bluetooth status. Anecdotal evidence suggests that BT is always on when the system reboots/freezes, but I have not paid close enough attention up to this point.

In the interim, anything else I can do? I was having the same problem with V15 prior to wiping and installing 16.

No, you should not.
Can you please state what your Graphics card model is or the output of

sudo lshw -c video


uname -a

sudo lshw -c video
[sudo] password for username:                
       description: VGA compatible controller
       product: Iris Plus Graphics 655
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 01
       width: 64 bits
       clock: 33MHz
       capabilities: pciexpress msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:139 memory:af000000-afffffff memory:40000000-7fffffff ioport:4000(size=64) memory:c0000-dffff
Linux NUC8i5BEH 5.11.0-38-generic #42~20.04.1-Ubuntu SMP Tue Sep 28 20:41:07 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

This is probably the source of your troubles. Iris.
Ubuntu did provide a patch that is in the (now) 5.10 kernel. I recommend trying this:

sudo apt install linux-oem-20.04

Reboot and be sure to boot into Advanced Options for Zorin by tapping the esc key or left shift key at boot. Arrow key down to zorin on 5.10.0-1051
Test that kernel thoroughly and if it works, then remove the 5.11 kernel.

Zorin lite freeze & reboot, and become unresponsive till forcefully reboot 4 times.
Please provide solutions, i want to shift to zorin but this issue don't have any solution. Required your suggestion to resolve this.

You have also posted the same here. Zorin 16 lite freeze and reboot
which has received a reply from Storm.

Please avoid duplicate posts, as it creates duplicated support effort.

Edited title.
Most promising solution: UNRESOLVED - Zorin 16 Pro reboots and freezes randomly - #7 by ltoolio

This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.