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July 7, 2025 - Problem: After cleaning my storage server, I received an error code 42 on my AsRock Rack X570D4U. Everything boots fine and reaches the normal 00, but then the error code switches to 42 just a few seconds later. The erro…

Level1Techs

forum.level1techs.com › hardware hub › build a pc

Asrock WRX80 Creator won't post, 5975x - Build a PC - Level1Techs Forums

September 15, 2022 - Problem: Asrock WRX80 Creator won’t post, error code stalls at 42, and occasianaly will stall at A2/A0, even after removing all devices except graphics card, 1 stick of ram and NVME SSD. Tested alternate graphics cards, all 8 ram modules in C1 (single stick boot), 2 ram modules in C1, D1; ...

Discussions

AsRock Z87 Extreme 4- error code 40 & 4f

For the past 5 hours my friend and i have been trying to put together a computer. we have checked all the cables, the CPU, everything we could think of. Ever time we try to start it up the Dr. Debug comes up with the number 40 then goes to 4f. any suggestions? More on forums.tomshardware.com

forums.tomshardware.com

February 12, 2019

ROG X670E-E Strix won’t post. (Code 42)

Was there a fix to this Im having the same issue I used the PC for about 5 days now its a no post and gives code 42 Im about to RMA it More on reddit.com

r/ASUS

October 24, 2022

I am getting astartup error code (42). What is it?__

Code 42: Windows cannot load the device driver for this hardware because there is a duplicate device already running in the system. A duplicate device was detected. This error occurs when a bus driver incorrectly creates two identically named sub-processes (known as a bus driver error), or ... More on answers.microsoft.com

answers.microsoft.com

November 20, 2009

ASRock motherboard error codes

Every PC builder eventually gets the memory slot order wrong. You have been baptized and can now join our club! More on reddit.com

r/homelab

August 24, 2025

Level1Techs

forum.level1techs.com › hardware hub › motherboards

List of Dr Debug BIOS Codes - Motherboards - Level1Techs Forums

March 28, 2017 - Recently I was busy troubleshooting an issue with my ASRock mainboard and Ryzen and I needed to lookup some of the Mainboard debug display error codes. As It turns out there aren’t really any official manuals I could find for this. So here are my debug codes that I could find and what they mean.

ASRock Forums

forum.asrock.com › forum_posts.asp

Debug error codes 37-42 - ASRock Forums

Greetings!I'm having some strange issues with a new build. Some basic Specs:ASRock 670e TaichiAMD...

reddit.com › r/pcbuild › [deleted by user]

[deleted by user] : r/PcBuild

December 7, 2022 - 42 is unstable memory move them to slots 2 and 4 if not working rrturn rhem and get a better kit. cordairs vengeance line of ram is plagued with mixxed binning of chips. id suggest team geoup kingston crucial or gskill as a replacement. ... As a side note in your motherboard's manual which ...

ASRock

asrock.com › support › index.asp

ASRock > Debug LED Troubleshooting Checklist

The codes that you see are status codes.

ManualsLib

manualslib.com › brands › asrock manuals › motherboard › z77 extreme4 › user manual

Dr. Debug - ASROCK Z77 Extreme4 User Manual [Page 42] | ManualsLib

February 25, 2016 - ASROCK Z77 Extreme4 Manual Online: Dr. Debug. Dr. Debug is used to provide code information, which makes troubleshooting even easier. Please see the diagrams below for reading the Dr. Debug codes. Status Code Description 0x00 Not used 0x01 Power on. Reset type detection (soft/hard)...

Tom's Hardware Forum

forums.tomshardware.com › home › motherboards

AsRock Z87 Extreme 4- error code 40 & 4f | Tom's Hardware Forum

February 12, 2019 - what processor do you have? on a forum on another website they problem was solved with a new chip http://www.pchelpforum.com/xf/threads/asrock-z77-extreme4-dr-debug-error-4f.151837/

XDA Developers

xda-developers.com › home › other hardware › the most commonly seen debug error codes on asrock motherboards, and how to fix them

The most commonly seen debug error codes on ASRock motherboards, and how to fix them

February 28, 2024 - We've detailed some of the most common errors on ASRock motherboards along with some possible fixes.

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reddit.com › r/asus › rog x670e-e strix won’t post. (code 42)

r/ASUS on Reddit: ROG X670E-E Strix won’t post. (Code 42)

October 24, 2022 -

So I’m coming over from an old Intel 8700k build and this has been absolute hell

I just slapped the board in (had to do an exchange because the previous one wouldn’t post either) with the following specs:

Cpu: Ryzen 9 7950x Gpu: RTX 3090 FE Ram: Corsair DDR5 Dom Plats for AMD - 2x16 6000 MHz 3 sata drives, 1 blank, 2 with just games and data 2 fresh nvme drives in the motherboard

And I keep getting code 42 with the q led lot being third from the left. I have done bios flashback to get the latest version but I’m at wits end on how to move forward, especially as 42 isn’t appearing in the manual! Any help would be appreciated as this has been the last two days of my life trying to get sorted.

Just got error code 99 too. Trying to fiddle with ram and pulling the drives with data off as well to at least get to bios

Top answer

1 of 5

Was there a fix to this Im having the same issue I used the PC for about 5 days now its a no post and gives code 42 Im about to RMA it

2 of 5

Error 42 for me went away after underclocking the RAM (leave xmp disabled in bios). Still early days of DDR5 so if it's not on the short QVL list it's down to luck. I got 64GB of 5200MHz (Corsair CMH32GX5M2B5200C40, 2 kits) that I couldn't get to work at that rating if my life depended on it. Kept sticking on Code 42 with a white QLED, gave up after waiting like an hour each (DDR5 takes a long time to boot, but an hour? = WTF) x 5 tries with various changes before resorting to letting it drop to auto settings (4800MHz, dunno what the timings are, auto as well). Sucks I paid like an extra $50-100 for overspec'd RAM that I couldn't get to use as advertised, maybe that will change with a newer bios if/when available. I guess it could be worse, some people simply can't get 4 sticks of certain vendors to work so are stuck with using half the ram they expected (ie 32GB instead of 64GB, a far bigger downgrade).

Asrock

download.asrock.com › Manual › WRX80 Creator R2.0.pdf pdf

Contact Information

42 · 0xE3 · PEI_S3_OS_WAKE · 0x50 · PEI_MEMORY_INVALID_TYPE · 0x53 · PEI_MEMORY_NOT_DETECTED · 0x55 · PEI_MEMORY_NOT_INSTALLED · 0x57 · PEI_CPU_MISMATCH · 0x58 · PEI_CPU_SELF_TEST_FAILED · 0x59 · PEI_CPU_NO_MICROCODE · 0x5A · PEI_CPU_ERROR · 0x5B · PEI_RESET_NOT_AVAILABLE ·

Microsoft Answers

answers.microsoft.com › en-us › windows › forum › all › i-am-getting-astartup-error-code-42-what-is-it › 243eeb6b-f346-4062-b95b-753b63515c42

I am getting astartup error code (42). What is it?__ - Microsoft Q&A

November 20, 2009 - Code 42: Windows cannot load the device driver for this hardware because there is a duplicate device already running in the system. A duplicate device was detected. This error occurs when a bus driver incorrectly creates two identically named ...

Asrock

asrock.com › support › faq.asp

ASRock > FAQ

Dr. Debug is used to provide codes that represent different errors that your system has encountered. Please see the diagram below for reading the Dr.

reddit.com › r/homelab › asrock motherboard error codes

r/homelab on Reddit: ASRock motherboard error codes

August 24, 2025 -

Update: Turns out my partner is infinitely smarter than I am. Rubber duck'd it with her and she pointed out I was looking at the memory slots upside down. I had the one stick of ram in slot A2 not A1 - which caused the F1 error.
Why the manual calls that "PEI_RECOVERY_USER" and not something memory related, I'll never know. But meh. It works now!

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TLDR: I have an ASRock B650D4U-2L2T/BCM that keeps getting stuck on an F1 POST code and I can't figure out what it actually wants from me.

TSWR (Too short, will read):

So last week I got an ASRock B650D4U-2L2T/BCM. Like a kid on Christmas I was all excited to build my first 8 bay NAS out of it.

Put everything together, tried to power it up. Found out the PSU I had was having trouble with the backplane of my CS382. So it really was just like Christmas. Got the toy, no way to power it.

Ordered another PSU, put it all together again yesterday and got... Nothing. Fans spin at full speed for about 8 seconds, then wind down after the 7 segment on the mobo sticks on F1.

No monitor ouput on VGA, HDMI or display port, no keyboard for input (plugged in but won't even give me the ability to hit numlock). Plugged in the OOB for it, let DHCP assign an IP (as much as it saddens me to have to put the OOB on my normal subnet, but since the OOB subnet has no DHCP and I have no way to set an IP without the machine booting...) and checked in there. No more information than before. Just a post code of 0xf1.
Checked the online manual for the board, it says that 0xf1 is "PEI_RECOVERY_USER"
It doesn't tell me what that means or how to even start fixing it.

So I assume bios is fried, upload a new version through OOB. OOB reports everything should be good, powercycle the machine for it to take effect. So I do just that.
Nothing still.

Pull battery and short the clear cmos pads, still nothing.
Pulled the CPU and memory to see if something else happened and it beeped at me with error codes that I just lobotomised it.

So now I'm here asking for help. What glaringly obvious troubleshooting have I missed?