If your computer doesn't recognize your connected device, you might see an unknown error or a '0xE' error. If you do, follow these steps and try to connect your device again after each step:

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1. Make sure that your iOS or iPadOS device is unlocked and on the Home screen.
2. Check that you have the latest software on your Mac or Windows PC. If you're using iTunes, make sure you have the latest version.
3. Make sure that your device is turned on.
4. If you see a Trust this Computer alert, unlock your device and tap Trust.
5. Unplug all USB accessories from your computer except for your device. Try each USB port to see if one works. Then try a different Apple USB cable.*
6. Restart your computer.
7. Restart your device:
8. Try connecting your device to another computer. If you have the same issue on another computer, contact Apple Support.
   

For more help, follow the steps below for your Mac or Windows PC.

* Learn how to connect iPad Pro (11-inch) or iPad Pro 12.9-inch (3rd generation) to your computer.

If you use a Mac

1. Connect your iOS or iPadOS device and make sure that it's unlocked and on the Home screen.
2. On your Mac, hold down the Option key, click the Apple menu, and choose System Information or System Report.
3. From the list on the left, select USB.
4. If you see your iPhone, iPad, or iPod under USB Device Tree, get the latest macOS or install the latest updates. If you don't see your device or still need help, contact Apple Support.
   

If you use a Windows PC

The steps differ depending on if you downloaded iTunes from the Microsoft Store or from Apple.

If you downloaded iTunes from the Microsoft Store

Follow these steps to reinstall the Apple Mobile Device USB driver:

1. Disconnect your device from your computer.
2. Unlock your iOS or iPadOS device and go to the Home screen. Then reconnect your device. If iTunes opens, close it.
3. Click and hold (or right-click) the Start button, then choose Device Manager.
4. Locate and expand the Portable Devices section.
   
5. Look for your connected device (such as Apple iPhone), then right-click on the device name and choose Update driver.
   
6. Select 'Search automatically for updated driver software.'
7. After the software installs, go to Settings > Update & Security > Windows Update and verify that no other updates are available.
8. Open iTunes.

If you downloaded iTunes from Apple

Follow these steps to reinstall the Apple Mobile Device USB driver:

1. Disconnect your device from your computer.
2. Unlock your iOS or iPadOS device and go to the Home screen. Then reconnect your device. If iTunes opens, close it.
3. Press the Windows and R key on your keyboard to open the Run command.
4. In the Run window, enter:
   %ProgramFiles%Common FilesAppleMobile Device SupportDrivers
5. Click OK.
6. Right-click on the usbaapl64.inf or usbaapl.inf file and choose Install.
   You might see other files that start with usbaapl64 or usbaapl. Make sure to install the file that ends in .inf. If you’re not sure which file to install, right-click a blank area in the File Explorer Window, click View, then click Details to find the correct file type. You want to install the Setup Information file.
7. Disconnect your device from your computer, then restart your computer.
8. Reconnect your device and open iTunes.

If your device still isn't recognized

Check Device Manager to see if the Apple Mobile Device USB driver is installed. Follow these steps to open Device Manager:

1. Press the Windows and R key on your keyboard to open the Run command.
2. In the Run window, enter devmgmt.msc, then click OK. Device Manager should open.
3. Locate and expand the Universal Serial Bus controllers section.
4. Look for the Apple Mobile Device USB driver.
   

If you don't see the Apple Mobile Device USB Driver or you see Unknown Device:

• Connect your device to your computer with a different USB cable.
• Connect your device to a different computer. If you have the same issue on another computer, contact Apple Support.

If you see the Apple Mobile Device USB driver with an error symbol:

If you see , , or next to the Apple Mobile Device USB driver, follow these steps:

1. Restart the Apple Mobile Device Service.
2. Check for and resolve issues with third-party security software, then restart your computer.
3. Try to install the usbaapl64.inf or usbaapl.inf file again.

I use a very cheap external numeric keypad on my MacBook Pro under Leopard, and it works fine. The first time I connected it to my MBP, tthe OS asked me what sort of keyboard it was, I answered ISO keyboard, and that's all.
I didn't notice any problem since. OK, I don't use iCal.

Bam! You nailed it for me. I had an old Toshiba external and that did it. Before the tip, OSX thought it was a full keyboard. Thanks!

I have a macbook with OS X, and holding down the num lock key while I connected the usb cable worked like a charm. It still said that the keyboad would need to be identified before it could be used properly, but I just closed that screen, went to excel, and the number pad worked fine. Broadcom driver update utility. Thanks for the tip!!

i bought a targus numeric keypad which is just for pc's but the second trick where i held the number lock down for over four seconds while it was plugged into my macbook made it work in programs that it was not working in before i tried. thanks for the tip.

My problem was that I had Mouse Keys turned on in the Universal Access system preferences panel. Once I turned that off, I got numbers again.

I had to sign up to post and say 'thank you' for this tip! I have a new 15' MacBook Pro and was having a problem trying to get my cheapo external number pad to work. The second trick -- holding down the Num Lock key for 4 seconds -- worked the second time I tried it. Also, I had to close the applications I was trying to use the number pad in and re-open them after holding down the Num Lock key before it would work. Thank you!!

Thank you so much! I do subtitling and CC's with Swift software installed on parallels. Swift Create uses numeric keyboard and I have been lugging around a huge keyboard because the numeric one wasn't working. I held down the num lock before plugging it in and now it works! Thank you!