How to fix the error “The ACPI BIOS in this system is not fully compliant”


Here’s a frustrating issue we came across – I thought I’d share it as in our research we didn’t find anything else on-line that could point to the true issue of the issue that we found.

The problem centred around a generic PC build (I can already feel you seasoned techies groaning as you read this…) with an Asus P5V-VM DH Motherboard. None too old – purchased possibly 18 months to 2 years ago. The issue was with a corrupt Operating System, but one which we had an Acronis TrueImage Workstationimage created for recovery from this exact situation. The problem? The Acronis Boot Disk would not boot up – despite having been demonstrated working in the past on the same system.

On each occasion, the recovery disk booted but then went to a black screen with no progress. We created a new Acronis Boot Disk from the latest downloaded TrueImage Workstation build – same result. We created a “Safe Mode” boot disk – same result.

We then tried booting from good old Barts PE– at which point we received the following error:-

“STOP: 0x000000A5 (Parameter1, Parameter2, Parameter3, Parameter4)
The ACPI Bios in this system is not fully compliant to the specification. Please read the Readme.txt for possible workarounds, or contact your system vendor for an updated bios.
The bios in this system is not fully ACPI compliant. Please contact your system vendor for an updated bios.”

This issue is well documented on the Microsoft Knowledgebase, but was surprising to find on a modern PC with an up-to date BIOS.

To test this theory, we booted from a Windows 2000, Windows XP, Windows Vista and even Windows 7 Install disks – all threw up exactly the same error – the BIOS in the system was not ACPI compliant.

So off we trundled to the Asus web-site and downloaded the latest beta BIOS for the system. Flash the BIOS, reboot – same error.

We tried re-flashing to earlier stable versions of the BIOS – same result – “The ACPI BIOS in this system in not fully compliant”.

Frustration turned to anger at Asustek. Who produces a non-ACPI compliant BIOS nowadays? Strangely though, all the documentation for the Motherboard suggested the BIOS *was* ACPI compliant – and we could see ACPI turned on in the BIOS menu. So what gives?

At this point the veteran geek in me came out and started looking at the issue through a series of deductions. If the Acronis Boot CD had worked before, what had changed since then? Then the realisation then hit that this PC had received a memory upgrade recently!

Checking the DIMM slots showed 2 x DIMMS – 1 x 1GB DDR2 533, and 1 x 2GB DDR 640. I removed the 1GB chip and voila! The PC sprang into life from the boot disk with no further problems.

The moral of the story? Don’t become so focused on what the error message is in situations like this, that you skip tried and tested troubleshooting steps. It’s been a while since I’ve done any Motherboard level troubleshooting like this, but back when I did this often, the problem was more often than not memory based.

Sadly my short run pretending to be a Technician again has to end, and I’ve got to go back to pretending to be a business owner again. It was fun whilst it lasted though! 🙂


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