Learn how to fix the “Pfsense CPU Doesn’t Support Long Mode” error. Our Pfsense Support team is here to help you with your questions and concerns.
How to Fix the “Pfsense CPU Doesn’t Support Long Mode” Error
If you have come across the error message “Pfsense CPU doesn’t support long mode”, you’re likely dealing with a hardware compatibility issue that prevents your system from running the 64-bit version of Pfsense.
Let’s break down this error message and take a look at how to fix it.
What Does “Long Mode” Mean?
Long mode is a CPU mode that allows a processor to execute 64-bit instructions, which is a requirement for running 64-bit operating systems like Pfsense 13. When a CPU lacks long mode support, it can only process 32-bit instructions, making it incompatible with 64-bit software.
Hence, this error happens when our system attempts to use a 64-bit kernel or OS on a CPU that only supports 32-bit processing.
Impacts of the Error
- The CPU cannot process 64-bit instructions without long mode, preventing Pfsense from booting.
- A 32-bit system can only address up to 4 GB of RAM, limiting the firewall’s ability to handle high traffic or intensive tasks.
- As the tech world moves to 64-bit computing, older 32-bit CPUs may struggle to run modern software.
- Tasks like deep packet inspection or high-bandwidth processing may slow down due to 32-bit constraints.
Causes and Fixes
1. The CPU Only Supports 32-bit Processing
Older CPUs may lack 64-bit (long mode) support.
Click here for the Solution.
- Check the CPU’s specs using tools like CPU-Z or visit the manufacturer’s website.
- If the CPU is only 32-bit, we must upgrade to a 64-bit compatible processor.
2. Virtualization Technology (VT-x) is Disabled in BIOS
Some systems require VT-x (Intel) or AMD-V enabled to support long mode.
Click here for the Solution.
- Access BIOS by pressing F2, F10, or Del during startup.
- Find Virtualization Technology under Advanced CPU Configuration and enable it. Save and reboot.
3. Running a 64-bit Kernel on a 32-bit CPU
If we accidentally downloaded the 64-bit Pfsense version, it won’t run on a 32-bit CPU.
Click here for the Solution.
- Download the 32-bit (i386) version from the official Pfsense site.
- Reinstall Pfsense using the correct architecture.
4. BIOS Set to Legacy Mode Instead of UEFI
Older BIOS modes might prevent 64-bit OS installation.
Click here for the Solution.
- Switch the BIOS from Legacy to UEFI mode.
- Access BIOS settings, select UEFI Boot Mode, and reboot. Ensure your installation media also supports UEFI.
5. Running a 64-bit Image on a 32-bit Virtual Machine Host
If we use virtualization software like VirtualBox or VMware, trying to run a 64-bit Pfsense image on a 32-bit host will cause this error.
Click here for the Solution.
- Verify that the hypervisor supports 64-bit Vms.
- Enable VT-x/AMD-V in both your BIOS and virtualization software settings.
6. Incompatible Pfsense Image (i386 vs. amd64)
A mismatch between the CPU architecture and the Pfsense version can cause compatibility issues.
Click here for the Solution.
- Double-check whether your CPU supports amd64 (64-bit) or only i386 (32-bit).
- Download the appropriate version of Pfsense from their official site.
Prevention: How to Avoid This Error in the Future
- Before installing Pfsense, confirm that your CPU supports long mode using tools like Speccy or CPU-Z.
- Consult the official Pfsense hardware guide https://www.pfsense.org to make sure the system meets minimum requirements.
- Enable Virtualization Technology and use UEFI mode to run a 64-bit OS.
- Keep the hardware up-to-date to avoid running into performance or compatibility bottlenecks.
[Need assistance with a different issue? Our team is available 24/7.]
Conclusion
Resolving this error will get our firewall back on track, whether by upgrading the CPU, adjusting BIOS settings, or choosing the correct Pfsense version.
In brief, our Support Experts demonstrated how to fix the “Pfsense CPU Doesn’t Support Long Mode” error.
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