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! 🙂


  • Richard Tubb2018-03-15 17:15:16

    This isn't something I'm able to help with Sofea. I wonder if anybody else might be able to help?

  • Sofea2018-03-14 09:45:19

    I tried with Skylake and push the iso Windows XP directly from using Out of Band Management steps. Then, I got this error. What should I do? My gateway is ECS-9210-700T16. I've tried with Haswell and it worked but not for Skylake. Any advice on this? Thanks!

  • Richard Tubb2017-02-22 13:26:26

    Thanks for the tip Steve! :-)

  • Richard Tubb2017-02-22 13:26:01

    Hey Francis -- having you tried contact Lenovo Support ( to see if there is a BIOS update available for your machine, or if indeed it's compatible with Windows 7? Let us know how you get on.

  • francis2017-02-08 20:37:49

    after changing my lenovo HDD and tried to install a win 7 OS on it it displays blue screen and this is the message that is comes with it "The ACPI Bios in this system is not fully compliant" what should I do?

  • SteveSi2017-01-22 10:19:54

    Hammering the F7 key as it boots often fixes it. My 6GB Lenovo IdeaPad 300 has this ACPI BIOS issue and repeatedly pressing F7 (or Fn+F7 depending on the BIOS setting for the Function keys) usually fixes the problem and allows it to boot to XP-based ISOs, etc.

  • Richard Tubb2016-12-06 17:32:22

    Glad to be of help Alessandro! :-)

  • Alessandro2016-11-24 01:32:53

    Yeah, it worked! Thank you! (GA-VM900M) :)

  • Richard Tubb2014-09-04 12:09:13

    Happy to have been of help - I'm glad my blog saved you time and money!

  • Remote Fix Laptop2014-09-03 07:22:04

    I was facing such problem with my PC for last a few days and this was really a great post as it helped me in fixing the ACPI BIOS issue with my system. It really saved my time and money as I was thinking to give my system to a computer repair shop to get fixed this issue.

  • Richard Tubb2014-06-08 13:04:30

    Dave - my pleasure! Really glad to hear the article was of help to you!

  • Dave2014-06-07 01:15:39

    Richard you're a life saver, i've been struggling with this problem for a week now. I've googled the question in a dozen different ways & tried a dozen different 'solutions'. Two identical sticks of 1gb memory & one has suddenly gone faulty. Thanks again

  • Richard Tubb2012-12-21 08:58:21

    Gary - you're welcome! I hope your PC holds up a while longer!

  • Gary2012-12-21 08:24:51

    Cheers mate! Had one stick of ram fail on me a few years ago so it´s been running on 3gb since then. It seems I´ve lost another one as removing another stick solved the exact same problem. Getting close to needing a new PC :-(

  • Richard2009-03-19 19:40:16

    Tim - you're right, of course, mixed memory not a good idea although it "should" work in theory. But there-in lies another lesson - never overlook the stuff that "should" work. :-)

  • Tim2009-03-19 13:26:24

    That makes sense, given that ACPI is loosely tied in with your system's memory (e.g. when you Hibernate). But surely having mixed memory anyway can't be helping the situation, ACPI issues aside?

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