Q: Lumia 800 won't start up during update by Zune This thread is locked from future replies

While tried several times to update my Lumia 800 (to OS 7.10.8840.142) by Zune it still doesn't work.

During step 6 of 10 (Restarting the phone) the Lumia shuts down, but won't start up again. It only fibrates 2 times (first around 1 second, then a very short pulse). I've waited serveral times for more than an hour, but nothing happens.
Untill I disconnect thet usb-cable, then after around  a minute Zune displays an error (801812 C 1). I tried several solutions from Microsoft (like, but the problem of restarting is never mentionted for this error code. I think that's because the error happens before Zune know's it's disconnected...

Who can help me?

The current version on my Lumia 800 is 7.10.8858.136 (newer than the update?!?)
Firmware: 1750.0823.8852.12430
Hardware: 112.1402.2.3
Software Radio: 8255
Bootloader Radio:
Chip Soc:




Hello Sander800:


Thank you for posting to the forum regarding your issue getting the Windows phone update to complete.  I have a couple suggestions at this point and some details that need to be gathered.


First, have you tried to update from another computer?  We have seen reports of this issue being caused by certain third party process running on a PC.  If you have yet to try connecting to a secondary computer, please do so.  If you are trying to do this from a work computer, try the update from a network that is less restrictive.


Next, we would like you to once again try the process outlined in the KB article you referenced:


For all other Windows Phones, a driver on your computer must be updated to resolve the issue.
A Windows Phone driver needed by the update was not installed on your computer in time. Try the update again. If you continue to receive this error, ensure that the Windows Phone driver is properly installed:

  1. Unplug the USB cable from the phone.
  2. Press and hold the Power
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    button until you see Slide down to power off, then flick down. After it’s off, press
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    to turn on your phone again.
  3. As soon as the phone turns on and vibrates, press and hold the Camera
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    button until the following "Connect to PC" screen appears. It may take a few moments for this to appear. Once the screen appears, you may release the Camera
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  4. Reconnect your phone using the USB cable.
  5. Validate that the Windows Phone driver is installed via Device Manager:
    1. Click Start, right-click Computer , and then click Properties.
    2. Click Device Manager.
    3. Expand Portable Devices. The model name of your phone should now be listed.
  6. If the entry under Portable Devices indicates an issue, run the Microsoft Fix It solution below. This solution will ensure your computer is correctly configured to receive driver updates.

    Fix this problem
    Microsoft Fix It 20024

    Note If there is no entry in the Device Manager for your phone, your computer is not recognizing that the phone is connected to it. Make sure that you're using the USB data sync cable which was included with your phone. You may also try another port on the computer, but don't use a USB hub or the ports located on the front of your computer. If available, use a compressed air duster to remove any dirt or debris from the USB port on the phone.
  7. If there are no issues, restart the phone: Press and hold the Power
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    button until the phone restarts.
  8. Try the update again.

If you continue to have this issue, provide the following details:

  • What do you see when you check device manager for your phone?
  • Have you attempted to update the drivers if the phone is showing in device manager?  If you have, what happened?
  • What OS is currently running on your PC?
  • What country are you currently located in?

Please let us know if you have any a new information, questions or concerns.


Mark W.


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Question Info

Views: 1,671 Last updated: February 26, 2018 Applies to: