Learn how to fix the ACPI “No Handler for Region” error in Proxmox. Our Proxmox Support team is here to help you with your questions and concerns.

How to Fix the ACPI “No Handler for Region” Error in Proxmox

According to our Experts, we are likely to run into the ACPI error “No handler for region” in Proxmox during the boot process.

This error indicates issues with how the operating system interacts with the system’s firmware. It indicates that the ACPI subsystem cannot locate a proper handler for a specific region.

Today, we will explore what this error means, how it affects our Proxmox server, and how to fix it.

What Causes the “No Handler for Region” Error?

This error is often due to :

• Incompatible or outdated BIOS/firmware
• Kernel compatibility issues
• Malfunctioning hardware
• Misconfigured virtual machines
• ACPI module conflicts

Impacts of ACPI Errors in Proxmox

• Users have reported Proxmox servers failing to boot after upgrades, with screens freezing at ACPI messages like “No handler for Region” or “Aborting method due to previous error.” This may also lead to some boot-time issues like VM quit or powerdown failure, further complicating server recovery.
• Faulty ACPI functionality may result in components not powering down or initializing properly, especially power management devices.
• Persistent ACPI errors have led to random crashes, reboots, and freezes.
• Power-saving features like sleep or hibernation modes may be disabled or dysfunctional. Consider using Proxmox backup modes that align with your server’s performance for stable backup strategies.
• Broken ACPI interactions can cause VMs to fail to start or operate inconsistently, especially when PCI passthrough is used. In some cases, even uploading ISOs for VM creation may require fallback methods like using command-line tools to bypass GUI limitations caused by system instability.
• Flooded logs make root cause analysis difficult, often hiding more serious underlying issues.
• Unexpected crashes linked to ACPI problems can lead to data corruption or forced reboots during critical operations.

How to Fix “No Handler for Region” in Proxmox

1. Update the BIOS

An outdated BIOS is a common cause of ACPI incompatibilities. We can update it with these steps:

1. First, identify the motherboard model.
2. Then, go to the manufacturer’s official support page.
3. Now, download the latest BIOS for the model.
4. Next, format a USB drive with FAT32 and extract the BIOS file.
5. After that, reboot the server and enter the BIOS setup.
6. Then, use the BIOS Flash utility to apply the update.
7. Finally, reboot and verify the updated version.

2. Adjust BIOS ACPI Settings

Misconfigured power management options can also lead to ACPI errors.

In this case, try these steps:

• Reboot and enter the BIOS setup.
• Locate the ACPI Settings, Advanced, or Power Management sections.
• Ensure ACPI Support is enabled.
• If unsure, load default settings.
• Save and exit BIOS.

3. Upgrade the Kernel in Proxmox

Some kernel versions may lack full ACPI support for our hardware.

apt update
apt dist-upgrade
reboot
Copy Code

We can verify the updated kernel version with this command:

uname -rCopy Code

4. Blacklist Problematic ACPI Modules

The `acpi_power_meter` module has been known to cause issues.

In this case, run this command:

nano /etc/modprobe.d/hwmon.confCopy Code

Then, add:

blacklist acpi_power_meterCopy Code

Now, save the file and reboot:

rebootCopy Code

5. Check Hardware Health

Faulty components can also trigger ACPI-related issues.

So, run these test:

1. Use Memtest86+ to check RAM.
2. Use SMART tools to check disk health:

   
   apt install smartmontools
   smartctl -t short /dev/sda
   smartctl -a /dev/sda
   Copy Code
3. Also, inspect the CPU temperatures and look for signs of motherboard damage.

6. Check Virtual Machine Configuration

Misconfigured VMs, especially with PCI passthrough, can trigger ACPI issues.

So, go through these steps:

1. Go to VM > Hardware in Proxmox GUI.
2. Then, verify that passthrough devices are properly configured.
3. After that, make sure IOMMU is enabled in the host BIOS.
4. Allocate enough CPU/memory to Vms.
5. Temporarily remove passthrough devices to test stability.

7. Reinstall Proxmox 

If system files are corrupt or errors persist despite fixes, try these steps:

1. Back up the VM data and configurations.
2. Download the latest Proxmox ISO.
3. Then, create a bootable USB and perform a clean install.
4. Alternatively, restore from a reliable backup.

Prevention Tips

To avoid ACPI issues in the future:

• Regularly update BIOS and firmware.
• Keep Proxmox and kernel packages up to date.
• Also, perform routine hardware checks and maintenance.
• Monitor logs for early warnings.
• Additionally, use best practices for VM passthrough and hardware resource allocation.

[Need assistance with a different issue? Our team is available 24/7.]

Conclusion

The “No handler for region” error in Proxmox signals that something is wrong with system firmware, kernel compatibility, or hardware. By addressing each cause, we can restore full stability to the Proxmox environment.

In brief, our Support Experts demonstrated how to fix the ACPI “No Handler for Region” error in Proxmox.