Boot Device LED being red signals either lack of a proper boot device with operating system installed (either USB or internal drive) or an issue with the boot device (mechanical/hardware failure) if there is already an OS or an OS installation disc technically available. Super IO is a monitoring chip installed on the motherboard. If the code refers to Super IO initialization failure, then the chip in question may be defective (If it's just Super IO initialization, then it means the board is hanging on this step probably because of the lack of a boot device). I would only entertain this possibility if you do have a proper known functioning boot device with an operating system installed connected to the motherboard in the first place. edit: some clarifications Answer from Mistywing on reddit.com
Reddit
reddit.com › r/pcmasterrace › code 99 on mobo super io initialization. has anyone ever had this issue? first boot. can’t get passed this screen.
r/pcmasterrace on Reddit: Code 99 on mobo super IO initialization. Has anyone ever had this issue? First boot. Can’t get passed this screen.
March 26, 2021 - How would you diagnose a Super IO initialization failure? r/pcmasterrace • · upvotes · · comments · My advice for a modern OS and UEFI configuration - get more performance and less latency! r/Amd • · upvotes · · comments · Having problem with my computer when i boot it up it just stays in the mobo logo and cant even go into bios.
Tom's Hardware Forum
forums.tomshardware.com › home › motherboards
Question - "Super IO initialization" Debug 99 error with new build ? | Tom's Hardware Forum
December 20, 2023 - "Super IO initialization" Debug 99 error. New build I’m getting just black screen and i can see 99 debug number on the motherboard When i press thr power button my aio fans are spinning, gpu seems to be reading power, and i can see the gigabyte aorus logo is lit up. Thr only thing that i did...
New PC build not fully booting and no post PLEASE HELP! :: Hardware and Operating Systems
An error Qcode 99 can be a Super IO Initialization and IO meaning anything connected to the board by any interface is not initializing. as you have just built the system, then it is reporting a device is not connected properly or there is a lack of power to a device causing the IO error. More on steamcommunity.com
Motherboard code 99 & no signal to screen. - PCPartPicker
Qcode 99 is "Super IO Initialization" and IO meaning anything connected to the board by any interface is not initializing. More on pcpartpicker.com
[Troubleshooting]I've got (error code) 99 problems, and it is definitely a bitch.
Boot Device LED being red signals either lack of a proper boot device with operating system installed (either USB or internal drive) or an issue with the boot device (mechanical/hardware failure) if there is already an OS or an OS installation disc technically available. Super IO is a monitoring chip installed on the motherboard. If the code refers to Super IO initialization failure, then the chip in question may be defective (If it's just Super IO initialization, then it means the board is hanging on this step probably because of the lack of a boot device). I would only entertain this possibility if you do have a proper known functioning boot device with an operating system installed connected to the motherboard in the first place. edit: some clarifications More on reddit.com
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February 18, 2014Motherboard code 99 & no signal to screen. - PCPartPicker
Qcode 99 is "Super IO Initialization" and IO meaning anything connected to the board by any interface is not initializing. More on no.pcpartpicker.com
Videos
Asus
rog-forum.asus.com › t5 › x99 › stuck-on-super-io-initialization › td-p › 603231
Stuck on super io initialization - Republic of Gamers Forum - 603231
March 6, 2024 - Hey first time posting here so don't be hard on me if i make any mistakes. I recently built my own pc and after assembling it i run it and i keep getting the q code 99. I tried soing some research to see what i need to do but i found nothing. Here are my specs: CPU: intel i7 5820k CPU Cooler: ...
MSI
forum-en.msi.com › home
MSI Tomahawk x870 First assembly stuck in 99 Super IO ...
August 13, 2025 - MSI Global English Forum
Facebook
facebook.com › groups › thedullclub › posts › 2883307211874379
Any solutions for post code 99 on AM5 motherboard?
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Steam Community
steamcommunity.com › discussions › forum › 11 › 144512526681393052
New PC build not fully booting and no post PLEASE HELP! :: Hardware and Operating Systems
Originally posted by Scottish Tablet:An error Qcode 99 can be a Super IO Initialization and IO meaning anything connected to the board by any interface is not initializing. as you have just built the system, then it is reporting a device is ...
PCPartPicker
pcpartpicker.com › forums › topic › 135510-motherboard-code-99-no-signal-to-screen
Motherboard code 99 & no signal to screen. - PCPartPicker
Qcode 99 is "Super IO Initialization" and IO meaning anything connected to the board by any interface is not initializing.
EVILBOX
evilbox.ro › windows › error-code-99-super-io-initialization
Error code 99 Super IO Initialization – EVILBOX
November 17, 2024 - On a brand new ROG STRIX X670E-E GAMING WIFI motherboard paired with a Ryzen 5950x CPU, and a G.SKILL Ripjaws S5 Black 64GB (2x32GB) DDR5 6000MHz CL30 Dual Channel Kit, after the update to the lastest BIOS v2506, date 2024/11/05 the board would fail to enter Windows 11 and hang with 99 Error ...
UEFI
uefi.org › specs › PI › 1.8A › V5_Super_I_O_Protocol.html
13. Super I/O Protocol — UEFI Platform Initialization Specification 1.8 Errata A documentation
The Super I/O Protocol is installed by the Super I/O driver. The Super I/O driver is a UEFI driver model compliant driver. In the Start() routine of the Super I/O driver, a handle with an instance of EFI_SIO_PROTOCOL is created for each device within the Super I/O.
Reddit
reddit.com › r/buildapc › [troubleshooting]i've got (error code) 99 problems, and it is definitely a bitch.
r/buildapc on Reddit: [Troubleshooting]I've got (error code) 99 problems, and it is definitely a bitch.
February 18, 2014 -
I finally received the final piece of my build today. And now I've spent the past 4-5 hours trying to get it to POST. I have an ASUS Z87-PRO and after numerous other codes, it has finally landed on Error code 99 when it boots up. And it doesn't just boot up all regular like, it boots up, goes through the cpu, memory, and gpu start up checks and then switches off, does them again, and finally ends up on the 99, with the "Boot device led" on and glowing red, an appropriately sinister color given the issues it has caused thus far.
Now the manual says that code 99 means "Super IO Initialization." I have no freaking idea what that means, but a little google-fu told me that I should try the following:
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completely remove the gpu, retry. - Did that, got 99.
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ensure there are no usb devices hooked up - check and double checked.
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If the mouse and keyboard are plugged in, make sure they're in a usb 2.0 port - Did that, also in 3.0, and not plugged in at all.
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reset CMOS - Done that one twice.
I'm pretty sure I've gone through and unplugged and replugged just about every cord in this thing, and this seems to be the extent of the internet's knowledge on this subject, at least as far as I can find. Does anyone have any more ideas?
TL;DR, my computer hates everything.
Top answer 1 of 2
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Boot Device LED being red signals either lack of a proper boot device with operating system installed (either USB or internal drive) or an issue with the boot device (mechanical/hardware failure) if there is already an OS or an OS installation disc technically available. Super IO is a monitoring chip installed on the motherboard. If the code refers to Super IO initialization failure, then the chip in question may be defective (If it's just Super IO initialization, then it means the board is hanging on this step probably because of the lack of a boot device). I would only entertain this possibility if you do have a proper known functioning boot device with an operating system installed connected to the motherboard in the first place. edit: some clarifications
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I’m having code 99 issues rn, it’s in white, I didn’t build this pc but it is a custom, it was a hand me down, it was working literally last night then it just stopped, like the actually pc part is still running it’s just the monitor won’t go anywhere beyond the black 99 screen
Reddit
reddit.com › r › PCBaumeister › comments › 1khnrd8 › super_io_initialization_99_nach_prozesserwechsel
Super IO initialization (99) หลังจากเปลี่ยนโปรเซสเซอร์
May 8, 2025 - ฉันเพิ่งประกอบ Ryzen 7 9800X3D ลงบนเมนบอร์ด Gigabyte Aours 670E Master ของฉัน ตอนนี้เมนบอร์ดขึ้นข้อความแสดงข้อผิดพลาด "อันลือลั่น" รหัส 99 (Super IO initialization) ฉันไม่ได้เสียบอุปกรณ์อะไรเลยนอกจากสาย Displayport และ BIOS ก็เป็นเวอร์ชั่นล่าสุดแล้วด้วย
Wikipedia
en.wikipedia.org › wiki › Super_I › O
Super I/O - Wikipedia
January 9, 2026 - Super I/O (sometimes Multi-IO) is a class of I/O controller integrated circuits that began to be used on personal computer motherboards in the late 1980s, originally as add-in cards, later embedded on the motherboards. A super I/O chip combines interfaces for a variety of low-bandwidth devices.
ComputerBase
computerbase.de › foren › arbeitsspeicher, mainboards und cpus › mainboards und cpus: probleme mit intel
Super IO inintialization | ComputerBase Forum
August 22, 2018 - "Qcode 99 is "Super IO Initialization" and IO meaning anything connected to the board by any interface is not initializing. If you have just built the system, then it is saying a device is not connected properly or there is a lack of power to ...
Reddit
reddit.com › r/asus › code 99?
r/ASUS on Reddit: Code 99?
June 17, 2022 - Qcode 99 is "Super IO Initialization" and IO meaning anything connected to the board by any interface is not initializing.
Electrónica Osmanys
electrogenios.com › integrado-super-io-en-una-placa-base
Integrado Súper IO en una placa base - Electrónica Osmanys
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Super User
superuser.com › questions › 1029458 › graphics-card-or-mainboard-defect
boot - Graphics card or mainboard defect? - Super User
January 21, 2016 - UPDATE: I tried another BIOS (changed the switch) and now I get Code 99: Super IO Initialization
Reddit
reddit.com › r/asus › x99 w/code 99
r/ASUS on Reddit: X99 w/code 99
June 1, 2024 -
I have a code 99 on my Asus X99 A-II, most likely caused by a virus from using a Tzurk brand AIO LCD screen. (Same issue with my AMD pc as well). Both occurring on the same day. With no video output, I’m at a loss on how to rectify this problem. Additional details/specs can be provided. Any tips are greatly appreciated.
Top answer 1 of 3
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Qcode 99 is called Super IO Initialization. meaning anything connected to the board interface is somewhat not initializing. Could be from a bad hdd, or as simple as removing any USB connected from mobo before booting up. Remove everything, any usb interface (mouse, keyboard and such) anything that's connected to any usb header from mobo then just leave the main parts, fans, cpu(ofc) and gpu then try booting it up. Go on from there then if that doesn't work, reseat ram maybe also cpu or even gpu. Could also mean it needs bios update but start with the easiest troubleshoot first. The aio screen u have, that connect via USB on mobo, correct? If so try disconnecting it first then booting up. I'm not sure how you got a virus unless you downloaded something sketchy from the web. Can u also send me a link of the aio screen your talking about? I want to check that out. here's a link where people manage to fix this issue doing different things
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I guarantee that you did not get a virus from connecting an AIO. Also a virus would affect the operating system and you wouldn’t see its effect during post. That being said…Code 99 could mean a lot of things. I recently experienced this and it was simply the bios letting me know that there was change and it wanted me to press F1 to continue and enter the bios. The problem was that my monitor (Samsung Oled G9) doesn’t initialize right away and since the post was halted, I never saw the message. I spent days unplugging ram, video card, etc. And I finally I tried an old monitor and boom right on the screen…Press F1 to run setup.
Dasharo
docs.dasharo.com › unified-test-documentation › dasharo-compatibility › 343-super-I-O-initialization-on-QubesOS
[PPS] Super I/O initialization - QubesOS - Dasharo Universe
This test aims to verify that the external PS/2 keyboard is detected correctly by the OPERATING_SYSTEM and that all basic keys work according to their labels · Test configuration data