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Getting A2 error code upon Restart / Warm Boot only !

gh0st47
Level 7
Just built my PC over the weekend. Here are the specs.

10900K
Maximus XIII Hero
Corsair Vengeance Pro 32GB 3200mhz CL16
1X 2TB Crucial MX500
2X 1TB Crucial MX500
1X 960GB Corsair MP510 ( Boot Drive )
RTX 2080 Super Strix

So whenever I'm on the Desktop, booted into Windows. If I were to Restart my PC, whenever the PC is booting up. I will get hit by a A2 error code.
My PC will be completely frozen, I can't even enter BIOS.
Even if I press on the Restart button on my casing, same thing. The PC restarts then freezes with A2 error code. But it be worst, my screen be blank. But I didn't lose signal to monitor.
I've FlexKey set to instant boot to BIOS, doesn't work either.

This only happen when I Restart my PC, never on a Cold Boot. Say now my PC is running, I click Shut Down. The moment my PC turn off and I power it on again. It will boot no issue no drama.

So in the beginning, I don't think the issue occur. Because when I've installed Windows, while I was updating Windows, installing software etc. Even when I restart my PC, it never happen even once before.
Till all sudden one day I needed to Restart my PC to adjust something in the BIOS and it started all sudden.

This time even if it's a program that requires me to restart, basically I click on the " Restart " on the program and not myself who manually clicking
" Start > Restart " I will face the same issue. The program will Restart my PC and upon booting up, A2 error code, PC frozen.

Things I've tried fixing this issue.

1) Reseated all my SATA cable
2) Reseated all my SATA power cable
3) Reset RAM to Default
4) Disabled Fast Startup in Windows
5) Disabled Hybrid Sleep
6) Disabled Hard Drive Power Off in Power Management
7) Change Boot to UEFI ( In the BIOS, by default it was Boot to Other OS )
😎 Check all my SSD and HDD Health ( well using Disk Info nothing serious, but all is fine, my SSD are all brand new except my HDD )
9) Run Crystal Mark to check if my SSD are all running at proper speed and they are.

No dice, nothing is working....I worry if this goes on, when Windows update come along I may face even bigger issues since I can't restart my PC properly...
What do you guys think is the issue ??
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8 REPLIES 8

Silent_Scone
Super Moderator
Hello,


What did you adjust in the BIOS prior the problem starting? Have you tried to reset the UEFI via the rear I/O panel?
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

Silent Scone@ROG wrote:
Hello,


What did you adjust in the BIOS prior the problem starting? Have you tried to reset the UEFI via the rear I/O panel?


Hmm nothing major honestly. But I can't remember exactly when it occur was it after or before.
But at the moment things I've adjusted.

-MCE Disable ( Enforce All Limit )
-Adjusted my Fan Speed
-XMP Profile 1

The Boot to UEFI etc things are later when I found out about this issue.
I thought I give it a try see if it works.

When you mentioned reset the UEFI via the rear I/O you mean Reset CMOS ??
I haven't actually try completely resetting my BIOS setting to defualt though to see if fixes it yet.

I will try it later.

One more IMPORTANT thing I must mention, actually I've only noticed this Restart issue exactly right when after I've uninstalled Corsair iCUE....
After the uninstallation of iCUE, it didn't ask me to Restart. I thought it would be a good practice to always Restart my PC after installing / uninstalling something that affect my system in any sort of way.

So I did it myself manually, it's right that moment the issue started. When I was Restarting, bam...hit with the A2 error code and it continue till now...

Silent_Scone
Super Moderator
The iCUE uninstallation could be a red herring, hard to say. Reset the UEFI and go from there.
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

Silent Scone@ROG wrote:
The iCUE uninstallation could be a red herring, hard to say. Reset the UEFI and go from there.


Damn...I hope it's nothing serious, I won't mind if it's just the stupid iCUE...
Actually I did try something yesterday..I didn't test it on the spot, but when I was about to turn off my PC and hit the bed, I thought I give it a try.
I " Restarted " my PC and it boot up fine ! I wonder if it's finally fixed....I haven't reset my UEFI yet.

I wonder if it's a fluke or stroke of luck !
Will try again tonight and see how it goes, I will definitely update here again. Fingers cross !

OK, finally I did it...I think I've nailed down the problem at least but not solve it...and it's not a good news either....
I believe the culprit is my W.D Black 2TB

Let me remind again that what drive my system have.

1X W.D Black 2TB ( It's partitioned into two partition, around 900GB each and this is an old drive from my previous system )
2X Curial MX500 1TB ( one is brand new, another is from previous system as well )
1X Crucial MX500 2TB ( brand new )
1X Corsair MP510 960GB ( brand new and it's my boot drive )

Ok methods I've tried and found out this is the drive causing issue.

1) Remove all SATA drives, Restart PC. PC Boot up fine reaches Desktop no drama.
2) Install my W.D Black 2TB first, startup PC, click Restart....bam instant hit with A2 error code when booting up. Just like usual.
3) Unplug my W.D Black 2TB, use a DIFFERENT SATA PORT on the Mobo, same thing...A2 error code
3) Unplug my W.D Black 2TB, connect one of my Crucial MX500 1TB drive. Boot up PC, reaches Desktop, click Restart, PC restarts instantly reaches Desktop no issue no drama....
4) At this point I was confident, I connect the rest of all my other SATA drives, EXCEPT my W.D Black 2TB, boot up, Restart. NO ISSUE !

So it's confirmed that my W.D Black 2TB is causing me Restart issue.
Nothing else, I've even re-install iCUE, disabled my RAM lighting and it's not the culprit.

I've updated one of my MX500 1TB drive Firmware too, it was outdated, that wasn't the culprit.
I've changed SATA port along with the cable ( basically I just switched my MX500 SATA connector with my W.D Black ), doesn't work so it's not the culprit.

I think we can be damn sure it's the W.D Black 2TB itself causinsg it....but biggest question is, WHY ONLY ON RESTART ???
Why it never happen during Cold Boot ??

Also prior to this, I notice another strange issue. My SSD would randomly disappear, I never notice it till I reach desktop and wanted to play my games.
STEAM show it's not downloaded that's when I found out, I thought maybe my SATA conneciton were loose. So I turn off my PC, check everything ( i didn't even bother unplug and replug them ) everything was fine.

So I just start up PC again, all my drives are there again.
Then today it happened again, this time I just shut down PC, turn it on again and it's fixed like before.
I wonder if it's the W.D Black 2TB causing this problem as well....??

Is this a Software / Hardware issue ?? This is weird as well...it feels like hardware, yet it feels like a software....

So what do I do at this point ?? Throw the W.D Black 2TB away ?? That's quite an important drive to me, since that's where I store all my videos etc....

gh0st47 wrote:
OK, finally I did it...I think I've nailed down the problem at least but not solve it...and it's not a good news either....
I believe the culprit is my W.D Black 2TB

Let me remind again that what drive my system have.

1X W.D Black 2TB ( It's partitioned into two partition, around 900GB each and this is an old drive from my previous system )
2X Curial MX500 1TB ( one is brand new, another is from previous system as well )
1X Crucial MX500 2TB ( brand new )
1X Corsair MP510 960GB ( brand new and it's my boot drive )

Ok methods I've tried and found out this is the drive causing issue.

1) Remove all SATA drives, Restart PC. PC Boot up fine reaches Desktop no drama.
2) Install my W.D Black 2TB first, startup PC, click Restart....bam instant hit with A2 error code when booting up. Just like usual.
3) Unplug my W.D Black 2TB, use a DIFFERENT SATA PORT on the Mobo, same thing...A2 error code
3) Unplug my W.D Black 2TB, connect one of my Crucial MX500 1TB drive. Boot up PC, reaches Desktop, click Restart, PC restarts instantly reaches Desktop no issue no drama....
4) At this point I was confident, I connect the rest of all my other SATA drives, EXCEPT my W.D Black 2TB, boot up, Restart. NO ISSUE !

So it's confirmed that my W.D Black 2TB is causing me Restart issue.
Nothing else, I've even re-install iCUE, disabled my RAM lighting and it's not the culprit.

I've updated one of my MX500 1TB drive Firmware too, it was outdated, that wasn't the culprit.
I've changed SATA port along with the cable ( basically I just switched my MX500 SATA connector with my W.D Black ), doesn't work so it's not the culprit.

I think we can be damn sure it's the W.D Black 2TB itself causinsg it....but biggest question is, WHY ONLY ON RESTART ???
Why it never happen during Cold Boot ??

Also prior to this, I notice another strange issue. My SSD would randomly disappear, I never notice it till I reach desktop and wanted to play my games.
STEAM show it's not downloaded that's when I found out, I thought maybe my SATA conneciton were loose. So I turn off my PC, check everything ( i didn't even bother unplug and replug them ) everything was fine.

So I just start up PC again, all my drives are there again.
Then today it happened again, this time I just shut down PC, turn it on again and it's fixed like before.
I wonder if it's the W.D Black 2TB causing this problem as well....??

Is this a Software / Hardware issue ?? This is weird as well...it feels like hardware, yet it feels like a software....

So what do I do at this point ?? Throw the W.D Black 2TB away ?? That's quite an important drive to me, since that's where I store all my videos etc....


Why not grab a WD Blue 2 TB SATA SSD and get rid of that old clunker? Yes it will set you back $200 but that drive will last a long time.

Falkentyne wrote:
Why not grab a WD Blue 2 TB SATA SSD and get rid of that old clunker? Yes it will set you back $200 but that drive will last a long time.


Hmm I don't mind replacing the drive. But I just wanna know for sure is it my W.D Black causing the issue, or it's something else.
I mean yeah without it my PC is restarting like normal.

But it make no sense, why does it only happen during Restart ?
Also, why is it so serious till the point that it will literally freezes my PC that I can't even enter the BIOS....

I guess I can find out by popping this drive to my previous system and test it...
Some said it's possible that the controller in it is dying, so after booting up when the drive is hot, the problem will occur...sound bit strange but yet possible i guess ?

I have absolutely no knowledge in IT, I don't major in this department lol....

MKCdn
Level 7

I have the same issue and symptoms, X299 Prime Deluxe II MoBo however and Win11 Pro. All NVMe drives. 4 x 1TB Mushkin in a RAID5 in an Asus Hyper M.2 PCIe card, Adata SX8200 500GB on the MoBo, and a Western Digital Black PC SN700 1TB as my Boot Drive in the other MoBo slot. Everything up-to-date. System is a rocket otherwise and no stability issues either. Green checkmarks and green lights everywhere I can run a test, benchmark or diagnostic BUT if I warm-boot.. I get the A2 Detect HDD code... it seems though IF I wait almost 10 minutes, it finally gets by the issue and Windows loads and everything is ok. Cold boots are fine. I'm a big fan of the WD NVMe line as I have several others but from the higher-end Black SN850X series. I THINK the problem might just be with this more-towards-the-bottom dweller in the product lineup. Performance tested it at 2-3 GB/s reads and writes but something about it isn't responding correctly when the BIOS says "ok guys, where's the OS?" ... and when called upon, my WD NVMe just sits there like an idiot. I also believe this began somewhere within the Win11 ecosystem and subsequent updates to it. I doubt I'll try to solve it other than just replacing the SN700 with a better NVMe.