Just a tiny ad can crash Windows 11 and make its Start menu and taskbar unusable

As you may already know, Windows 10 and Windows 11 are able to show promotional messages to the user right on the desktop. In order to promote integration of the upcoming Windows 11 with Microsoft Teams, Microsoft pushed such an ad to Insiders. But Explorer (that implements the shell of the Windows desktop) stopped responding, leaving users without a working Start menu and taskbar. That's what we wrote about on Friday. Here are some details on this issue.


Getting a non-working system due to ads is not users could expect, even when running a pre-release build. However, this is exactly what happened to those who installed Windows 11 Build 22000.176 or Build 22449, which are the latest preview updates for the Beta and Dev channels, respectively.

Windows 11 Desktop With Start Menu And Taskbar

After several complaints, Microsoft acknowledged the problem and posted a quick fix to affected users. They are prompted to open the registry editor (regedit) through the task manager and make some changes. However, the company did not explain the cause of the issue in detail. So a third-party researcher got that done.

What really happened

Daniel Aleksandersen, developer of Edgedeflector, found out that the problem was caused by a small ad configuration file. A Windows component called IrisService was fetching that file from servers. That service is a part of Windows Spotlight that also downloads Lock Screen Images, their details, and so on.

Based on the solution provided by Microsoft, Daniel Aleksandersen was able to localize the problem by locating it in a registry key containing a serialized JSON binary. This large object contained advertisements for Microsoft Teams.

Microsoft says the bug affects devices that have received a server patch. The company also said  that the released preview builds are safe to use. However, the situation itself, when you can get an unusable OS due to a simple ad, is somewhat wrong. If so, Microsoft should review the architecture design of the Windows 11 shell to make it more reliable. What other surprises can you expect after October 5, when Windows 11 will be available to everyone?

Support us

Winaero greatly relies on your support. You can help the site keep bringing you interesting and useful content and software by using these options:

If you like this article, please share it using the buttons below. It won't take a lot from you, but it will help us grow. Thanks for your support!


Author: Sergey Tkachenko

Sergey Tkachenko is a software developer who started Winaero back in 2011. On this blog, Sergey is writing about everything connected to Microsoft, Windows and popular software. Follow him on Telegram, Twitter, and YouTube.

One thought on “Just a tiny ad can crash Windows 11 and make its Start menu and taskbar unusable”


Leave a Reply

Your email address will not be published.

Using Telegram? Subscribe to the blog channel!
Hello. Add your message here.