# Computer problem: USB hub not recognized **URL:** \ **Category:** Factual Questions\ **Created:** [November 8, 2009, 7:49pm UTC](https://boards.straightdope.com/t/computer-problem-usb-hub-not-recognized/516831 "2009-11-08T19:49:45Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![DarrenS](https://avatars.discourse-cdn.com/v4/letter/d/977dab/32.png) [@DarrenS](https://boards.straightdope.com/u/DarrenS)\ **Post date:** [November 8, 2009, 7:49pm UTC](https://boards.straightdope.com/t/computer-problem-usb-hub-not-recognized/516831/1 "2009-11-08T19:49:45Z")
I’ve Googled this to death, read the relevant FAQs, and _almost_ got it to work. Windows XP, SP3. It’s a Dell 530S desktop. I have a non-powered 6-port USB hub. (I know that can be an issue, but I have no reason to suspect a power problem.) It works fine on my Linux machine, so it’s known good. When I plug the hub into my Windows box, it sees it but says it is not working and eventually installs as “Unknown Device”. Repeatedly uninstalling/unplugging and “scanning for hardware changes” produces the same result. Same behavior on front and rear USB ports (sometimes front ones are not wired correctly). Other USB peripherals work fine on this computer. Here’s the kicker: I tried the USB cleanup procedure explained [here.]([http://http](http://http)://www.usbman.com/Guides/Cleanup Device Manager Safe Mode.htm) Unfortunately there’s no PS2 port, so I have a USB mouse and kb, making it impossible to remove _all_ USB devices, but I removed everything else. (I though of using Terminal Services from another machine, but that doesn’t work in Safe Mode.) Anyways…when I deleted the hub to which the “unknown device” is attached, in Safe Mode, Windows started doing its “found new hardware” dance…and successfully found my hub, and listed, correctly, the devices attached to it! “Found Saitek joystick…found HID” – both correct. Alas, it then _continued_ “finding new hardware” and ended up with “unknown device”, apparently no longer recognizing the hub or the things attached to it. After that initial success, even when I repeat the process it ends up with “unknown device”. The device has no manufacturer’s name written on it, but I suspect custom drivers aren’t required because it _did_ correctly detect everything, just once. Any ideas? ---
**Author:** ![DarrenS](https://avatars.discourse-cdn.com/v4/letter/d/977dab/32.png) [@DarrenS](https://boards.straightdope.com/u/DarrenS)\ **Post date:** [November 8, 2009, 8:10pm UTC](https://boards.straightdope.com/t/computer-problem-usb-hub-not-recognized/516831/2 "2009-11-08T20:10:11Z")
In case it’s useful: IRQ list (from msinfo32) after everything is “installed”, including the “unknown device”. IRQ 0 High precision event timer OK IRQ 8 High precision event timer OK IRQ 9 Microsoft ACPI-Compliant System OK IRQ 11 Intel 82372FB System Management Bus Controller OK IRQ 13 Numeric data processor OK IRQ 16 Intel® G33/G31/P35/P31 Express Chipset PCI Express Root Port - 29C1 OK IRQ 16 NVIDIA GeForce 8400 GS OK IRQ 16 Intel® ICH9 Family USB Universal Host Controller - 2937 OK IRQ 18 Intel® ICH9 Family USB2 Enhanced Host Controller - 293C OK IRQ 18 Intel® ICH9 Family USB Universal Host Controller - 2936 OK IRQ 19 Intel® ICH9 Family USB Universal Host Controller - 2939 OK IRQ 19 Intel® ICH9 Family USB Universal Host Controller - 2935 OK IRQ 19 Intel® ICH9R/DO/DH 4 port Serial ATA Storage Controller 1 - 2920 OK IRQ 19 Intel® ICH9 Family 2 port Serial ATA Storage Controller 2 - 2926 OK IRQ 20 Intel® 82562V-2 10/100 Network Connection OK IRQ 21 Intel® ICH9 Family USB Universal Host Controller - 2938 OK IRQ 21 802.11g Wireless PC Card/PCI Adapter OK IRQ 22 Microsoft UAA Bus Driver for High Definition Audio OK IRQ 23 Intel® ICH9 Family USB Universal Host Controller - 2934 OK IRQ 23 Intel® ICH9 Family USB2 Enhanced Host Controller - 293A OK USB info, also from msinfo32: HID Keyboard Device HID\VID\_413C&PID\_2003\6&2C74F329&1&0000 HID-compliant mouse HID\VID\_046D&PID\_C50A\6&6646650&0&0000 Intel® ICH9 Family USB Universal Host Controller - 2934 PCI\VEN\_8086&DEV\_2934&SUBSYS\_020D1028&REV\_02\3&2411E6FE&0&E8 Intel® ICH9 Family USB Universal Host Controller - 2935 PCI\VEN\_8086&DEV\_2935&SUBSYS\_020D1028&REV\_02\3&2411E6FE&0&E9 Intel® ICH9 Family USB Universal Host Controller - 2936 PCI\VEN\_8086&DEV\_2936&SUBSYS\_020D1028&REV\_02\3&2411E6FE&0&EA Intel® ICH9 Family USB Universal Host Controller - 2937 PCI\VEN\_8086&DEV\_2937&SUBSYS\_020D1028&REV\_02\3&2411E6FE&0&D0 Intel® ICH9 Family USB Universal Host Controller - 2938 PCI\VEN\_8086&DEV\_2938&SUBSYS\_020D1028&REV\_02\3&2411E6FE&0&D1 Intel® ICH9 Family USB Universal Host Controller - 2939 PCI\VEN\_8086&DEV\_2939&SUBSYS\_020D1028&REV\_02\3&2411E6FE&0&D2 Intel® ICH9 Family USB2 Enhanced Host Controller - 293A PCI\VEN\_8086&DEV\_293A&SUBSYS\_020D1028&REV\_02\3&2411E6FE&0&EF Intel® ICH9 Family USB2 Enhanced Host Controller - 293C PCI\VEN\_8086&DEV\_293C&SUBSYS\_020D1028&REV\_02\3&2411E6FE&0&D7 USB Human Interface Device USB\VID\_413C&PID\_2003\5&37AACC89&0&1 USB Human Interface Device USB\VID\_046D&PID\_C50A\5&37AACC89&0&2 USB Root Hub USB\ROOT\_HUB\4&39E334E0&3 USB Root Hub USB\ROOT\_HUB\4&3977EE9F&2 USB Root Hub USB\ROOT\_HUB\4&179223DB&2 USB Root Hub USB\ROOT\_HUB20\4&24CDE621&3 USB Root Hub USB\ROOT\_HUB\4&715777&1 USB Root Hub USB\ROOT\_HUB\4&14FDF0FC&4 USB Root Hub USB\ROOT\_HUB\4&1E8EF8FA&4 USB Root Hub USB\ROOT\_HUB20\4&A57E816&9 Unknown Device USB\VID\_0000&PID\_0000\5&36609A74&0&4 ---
**Author:** ![xash](https://avatars.discourse-cdn.com/v4/letter/x/c6cbf5/32.png) [@xash](https://boards.straightdope.com/u/xash)\ **Post date:** [November 8, 2009, 11:28pm UTC](https://boards.straightdope.com/t/computer-problem-usb-hub-not-recognized/516831/3 "2009-11-08T23:28:41Z")
It’s difficult to diagnose this without actually being at the computer, because it’s a lot of trial and error in these cases, but try some of this: Manually select a driver for the Unknown Device (try with some generic or brand USB hub drivers) Make sure the USB cord from your computer to the hub is short. Try with other cords If your mouse/keyb are USB, switch around the USB ports and try the hub with each of the ports (or, if you remember which USB port recognized your device briefly, stick to that one because at least you know the hardware recognizes it correctly) Update to the latest BIOS (be very careful with this), then go into the BIOS and mess with the IRQ settings there (this has a tendency to screw up other stuff, so make sure you record all changes so you can change back) Go into the BIOS and look for other options that may be relevant ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [November 8, 2009, 11:49pm UTC](https://boards.straightdope.com/t/computer-problem-usb-hub-not-recognized/516831/4 "2009-11-08T23:49:03Z")
> [@DarrenS](#): > > Windows XP, SP3. It’s a Dell 530S desktop. > > I have a non-powered 6-port USB hub. (I know that can be an issue, but I have no reason to suspect a power problem.) I’ve had big problems in the past with Dell boxes and portable HDDs that want to be powered by the USB port. ---
**Author:** ![DarrenS](https://avatars.discourse-cdn.com/v4/letter/d/977dab/32.png) [@DarrenS](https://boards.straightdope.com/u/DarrenS)\ **Post date:** [November 10, 2009, 4:42am UTC](https://boards.straightdope.com/t/computer-problem-usb-hub-not-recognized/516831/5 "2009-11-10T04:42:57Z")
It’s working now…but I’m still not exactly sure how. One thing I did was [configure Device Manager to show “non present” devices.](http://support.microsoft.com/kb/241257) Once I did this, I saw a bunch (dozen or more) of “unknown devices” under USB, as well as “composite USB devices”. All were grayed out, i.e. “non present”, so I removed all of them. Then I scanned for new hardware, it found the USB hub and attached devices, which now work. It tried to continue installing some other “USB hub” but I told it not to, earning me a yellow exclamation point in Device Manager. However, everything seems to be working. Thanks for the suggestions.