FIX: Windows 10 Upgrade Assistant is stuck at 99%

Worried that Windows 10 Upgrade Assistant is stuck at 99%? Apparently, the setup download procedure works as intended, but the problems arise in the final installation segment.

Sometimes a hefty dose of patience is all you need. As stated by Microsoft technicians, this isn’t an error. Basically, if there’s an upgrade error at hand, you’ll be timely prompted.

Since this occurrence isn’t followed by any kind of error prompt, we can concur that all you should do is simply wait and Windows Upgrade Assistant will finish the installation.

On the other hand, certain Windows 10 users reported that the 99% installing stuck issue lasted up to 24 hours which is, to say the least, ludicrous. With that in mind, we advise you to wait up to 20 minutes.

If the Assistant is still stuck at 99%, it’s time to take action. For that purpose, we prepared a list of possible solutions in order to help you to troubleshoot this issue.

How do I fix Windows 10 Upgrade Assistant stuck at 99%?

1. Disable third-party antivirus temporarily

Even though Windows Defender is great protection-wise, some people are more fond of third-party antivirus solutions. That’s a reasonable choice for various reasons.

But, on the other hand, third-party anti-malware solutions occasionally tend to create a stir within the system. Some of them might even block the upgrade process.

Now, don’t get us wrong, we don’t advise you to ditch a third-party solution in favor of Windows Defender. However, you can disable the real-time protection for a limited period of time, until the upgrade installs, or even remove it.

Don’t know how to remove the antivirus from your PC? Check out this list with the best uninstaller software you can use right now.

2. Unplug peripheral devices

The fact that Windows Update in Windows 10 covers drivers can also be the cause of the problem. Too many outdated peripheral devices can certainly cause turmoil in the upgrade process.

So, just for the sake of trying, make sure to unplug all peripheral devices from USB ports. Additionally, if you have the USB-C SD card reader or any other similar device, unplug those, too.

Of course, this doesn’t include mouse and keyboard. Once the procedure is finished, you can plug in all devices and deal with drivers later on. You may then use this handy guide to update drivers like a pro.

If the problem is persistent and upgrade is stuck, give it another try but, this time without the peripheral devices. In case it still misbehaves, continue with the troubleshooting.

3. Disable connection temporarily

Some users were able to resolve this issue by disabling the connection. For some odd reason, the stable connection affects negatively the upgrade process.

So, you can try unplugging your Ethernet cable, disabling Wi-Fi and then you should look for changes. They should be visible immediately after the connection is disabled.

If that’s not the case, you can restart the upgrade procedure and, right after the download is finished, cut the connection again. Nonetheless, this might not work for everyone.

4. Restart Windows Update service

1. In the Windows Search bar, type services, and open Services.
2. Scroll down until you reach the Windows Update service.
3. Right-click and press Stop, and then repeat the action but click Start instead.
4. That should resolve the stall and the installation process should continue.

Another valid troubleshooting step is to restart the Windows Update service. This covers all update-related processes, including the Windows Upgrade Assistant.

Occasionally, this service can stop working for no apparent reason and this will, consequently, prevent the upgrade operation from finishing.

5. Perform a clean system reinstallation

1. Download Media Creation Tool from this link.
2. Plugin the compatible USB flash drive.
3. Run Media Creation Tool and accept the License Terms.
4. Select ‘Create installation media (USB flash drive, DVD, or ISO file) for another PC’.
5. Choose the preferred language, architecture, and edition, then click Next.
6. Choose the USB flash drive option and click Next.
7. Media Creation Tool will download the setup and copy the installation files on the USB flash drive.
8. You may now restart your PC.
9. In the initial boot screen, press F10, F11, or F12 to access the Boot menu. It differs depending on your motherboard.
10. Choose USB flash drive as a primary bootable device and the Windows 10 Setup should commence immediately.
11. Follow the instructions and you should be good to go.

Finally, if you’re repetitively unable to upgrade your system, the last resort lies in the clean reinstallation. Ages ago, the reinstallation was a lengthy and complicated procedure, but that’s not the case in Windows 10.

Besides the bootable media, like USB or DVD, it takes only the Media Creation Tool to make it work.  You’ll need a USB flash drive with at least 4 GB of free space in order to create a bootable installation drive.

Of course, before we start, it’s of supreme importance to backup your data on the secondary partition or to an external drive, since you’ll wipe clean the system partition.

In addition, backup your license key because you might need it later on. You may use some of the best local data backup software tools of the moment in that regard.

Was there a problem running Windows 10 Media Creation Tool? Fix it with the help of this complete guide.

That should do it. In case you have any questions regarding this Windows 10 Upgrade Assistant issue, make sure to post them in the comments section below.

FAQ: Learn more about Windows 10 Upgrade Assistant

• How long does it take to upgrade to Windows 10?

Be prepared for any frame between 15 minutes and 3 hours to upgrade to Windows 10 on a modern PC. The in-place upgrade usually takes more time since Windows needs to back up all current data.

• Can I stop a Windows 10 update in progress?

You can easily stop a Windows 10 update in progress by following this path: Control Panel > System and Security > Security and Maintenance > Maintenance.

Under Automatic Maintenance, you just need to select Stop Maintenance.

Editor’s Note: This post was originally published in September 2017 and has been since revamped and updated in March 2020 for freshness, accuracy, and comprehensiveness.