FIX: Windows installation encountered an unexpected error

Aleksandar Ognjanovic
by Aleksandar Ognjanovic
Troubleshooting Expert
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  • Installing a fresh new copy of Windows 10 is usually the go-to solution for fixing pretty much any OS-related issue.
  • Various hardware issues can cause a Windows 10 install to fail. When that happens, simply follow the steps below for some quick troubleshooting steps.
  • This particular issue is just one of many Install errors that we have covered, so make sure you visit the page for more related articles.
  • We have a dedicated Fix page where you can find troubleshooting guides on all matters Windows 10-related.
troubleshoot windows 10 install fail

In comparison to previous Windows iterations, installing Windows 10 is rather simple. Especially since almost everything, including drivers, is managed by the system itself.

Also, software distribution is much simple nowadays with the Media Creation Tool. However, this, on a paper simple procedure, posed quite a burden for various users.

The Windows installation encountered an unexpected error prompt and the consequent installation failures are not uncommon.

In order to address this, we prepared a list of possible solutions. If you’re stuck with this error after multiple tries, make sure to check the steps we provided below.


How do I  fix the Windows installation error?

  1. Check the system requirements
  2. Check RAM and HDD
  3. Switch USB port and the USB drive
  4. Remake the installation media with the Media Creation Tool

1. Check the system requirements

Let’s start with compatibility. Windows 10 isn’t exactly too distinct from Windows 7 when it comes to system requirements. However, there are some disparities, and you should take them into account if you’re installing Windows 10.

Extra RAM here and a tad more storage space there can make a great difference.

Here are the system requirements you’ll need to meet in order to install Windows 10:

  • CPU: 1 gigahertz (GHz) or faster processor or SoC
  • RAM: 1 gigabyte (GB) for 32-bit or 2 GB for 64-bit
  • HDD space: 16 GB for 32-bit OS 20 GB for 64-bit OS
  • GPU: DirectX 9 or later with WDDM 1.0 driver
  • Display: 800×600windows installation encountered an unexpected error

If you met the system requirements, make sure that your installation media is well-created.


2. Check RAM and HDD

  1. Download the USB version of MemTest86, here.
  2. Plug in the USB. Have in mind that this procedure will erase all its data.
  3. Extract (unzip) the file and run “imageUSB tool“.windows installation encountered an unexpected error
  4. Select the USB drive and create a bootable drive.
  5. Restart your PC and boot from a USB drive.

Amongst the various hardware issues which can cause installation errors, RAM and HDD sit at the top.  We suggest investigating RAM health with the third-party tool called MemTest86.

This tool is highly regarded as the best for the job. The thing with it is that you’ll need to mount it on the bootable media in order to work.

HDD-wise, you can use the built-in utility or resort to third-party tools to check for bad sectors and health issues.

  1. In the Windows Search bar, type cmd, right-click on Command Prompt and run it as an administrator.
  2. In the command line, type the following command and press Enter:
    • chkdsk c: /rwindows installation encountered an unexpected error
  3. Wait until the procedure ends.

Another thing you can try if the error is persistent after you click Install is formatting the drive via the Command Prompt. This is what you need to do:

    1. When the bootable USB drive boots, click Repair your computer.
    2. Choose Troubleshoot.
    3. Click Command Prompt.
    4. In the command line, type the following commands and press Enter after each:
      • diskpart
      • list volume
    5. Now, you should see what’s the number beside your system partition. Remember it. Will use “3” as an example. Act with caution and make sure you’re not selecting the data partition. If everything is merged in one partition
    6. Enter the following commands and press Enter:
      • select volume 3windows installation encountered an unexpected error
      • clean
    7. After that, close the Command Prompt and try installing Windows 10 again.

3. Switch USB port and the USB drive

Another thing which seemingly slips under the radar is the installation media itself. Even though the majority of USB thumb drives with 6 or more gigs of space will suffice, some might not.

For that reason, if possible, switching to an alternative USB flash stick might get you going. As a side note, we recommend sticking with the 2.0 USB drives if you’ve never installed Windows 10 and enabling USB legacy in the BIOS settings.

On the other hand, even if the bootable USB drive works fine, the problem might be within the USB port you’re using. Some users managed to address the issue at hand by simply restarting the PC and switching between the USB ports.

Finally, you can, if the circumstances allow, try using an ISO file to create a bootable DVD.


4. Remake the installation media with the Media Creation Tool

  1. Download the Media Creation Tool from here.
  2. Plug in the USB flash drive with at least 6 GB.
  3. Run Media Creation Tool and accept the License Terms.windows installation encountered an unexpected error
  4. Choose Create installation media (USB flash drive, DVD, or ISO file) for another PC.windows installation encountered an unexpected error
  5. Choose the fitting language, architecture, and edition and click Next.windows installation encountered an unexpected error
  6. Select USB flash drive and then click Next.windows installation encountered an unexpected error
  7. Media Creation Tool will download the setup and copy the installation files onto the USB flash drive.
  8. Restart your PC and boot with the newly-created installation media.

In the end, if none of the previous steps resolved the issue at hand, we encourage you to remake the bootable drive. The best and the most favorable way is to use the Media Creation Tool.

With that said, the whole procedure is rather simplified and it won’t last too much. Of course, this depends on your bandwidth speed. Due to unwelcome circumstances, you can use any other PC to create a bootable installation media for Windows 10.


FAQ: Learn more about failed Windows 10 installs

  • Is installing Windows 10 easy?

The install process for Windows 10 is arguably the simplest of them all. However, if you encounter issues with the process, read this in-depth guide for more information.

  • What should I do if I encounter an error while installing Windows 10?

Try to remake the installation media with the Media Creation Tool. If you’re having issues with that tool, refer to this article for some troubleshooting guides.

  • Can software issues be the cause of failed Windows 10 installs?

If the Windows 10 ISO image is properly written on your installation media, then the only issues that can cause a failed Windows 10 install is a hardware issue.


After that, you should be able to install Windows 10 without any issues whatsoever. If the error is persistent, we recommend contacting your computer OEM.

And on that note, we can wrap it up. In case you have some additional questions or suggestions, feel free to share them with us. You can do so comfortably in the comments section below.

Editor’s Note: This post was originally published in [date of publishing] and has been since revamped and updated in [date of republishing] for freshness, accuracy, and comprehensiveness.

Editor's Note: This article was originally published in May 2018 and was revamped and updated in June 2020 for freshness, accuracy, and comprehensiveness.
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