Windows 11 KB5055523 creates “inetpub” folder out of nowhere

After installing the Windows 11 KB5055523 (24H2) update for Windows 11, Windows Latest noticed that an unexpected “inetpub” folder is being created in the Windows installation drive. Based on our tests, this folder appears even on systems that don’t have IIS (Internet Information Services) installed.

If you see the “inetpub” folder mysteriously appear on your PC, don’t freak out. It is an expected change, according to an updated document by Microsoft. It’s worth noting that the “inetpub” folder isn’t just a random name because it’s typically created by IIS (Internet Information Services).

According to Microsoft’s support documentation, IIS (Internet Information Services) is a web server software for developers created by Microsoft. It’s not used by regular users, but if you’re a developer, you might use IIS (optional component) to host websites and web apps on Windows.

It is used to serve web pages locally, so developers can test stuff, but regular users don’t need it. In other words, this folder isn’t supposed to appear on regular PCs where IIS is not even turned on, but a change in the operating system causes it to appear for everyone.

Why Windows 11 KB5055523 is creating inetpub folder?

While it’s impossible to know what exactly happened, based on my testing, this could be the likely scenario:

1. Windows Update automatically installs KB5055523 because it’s designated as a “security patch” with critical fixes.
2. While it’s not mentioned in the changelog, it’s possible the update included some changes for IIS (Internet Information Services) components, maybe for testing or something else.
3. This caused IIS to get enabled automatically, or some IIS features were turned on for a little while. But how something like that could happen? Maybe Windows 11 KB5055523 changed Windows features or added web-based tools (like HTTP.sys or IIS dependencies). Or there this was created by a system process for a security patch.
   
4. At this point, IIS is enabled, or a related feature is triggered to fix a security patch, and that’s enough for Windows to automatically create the C:\inetpub folder.
5. C:\inetpub folder is the default folder to store web content (like websites hosted by IIS).

As you can see in the above screenshot, the folder is empty, and the size is zero bytes on the drive. This is because I am not hosting any website using IIS, so the folder is empty, but when you host a website using IIS, Windows would also create wwwroot subfolder (for web pages), logs, and config files.

Also, on all my PCs or affected PCs, IIS is turned off:

Windows 11 KB5055523 is creating inetpub folder even on vanilla installations

Windows Latest found the “inetpub” folder on the installation drive (C drive) on all our PCs and virtual machines, even when we clean installed Windows 11 24H2 and then applied KB5055523.

While KB5055523 doesn’t mention IIS or anything web-server-related in its changelog, it does include security fixes. The folder is related to one of the security changes, so there’s no need to delete it.

Update: Microsoft has now updated the support document to clarify the folder is associated with a security patch (CVE-2025-21204) and should not be deleted. However, Microsoft is not going to explain why a folder is required for the security patch, which is typically needed for IIS (Internet Information Services) logs.

If you deleted the folder, you just need to turn on the IIS (Internet Information Services) from the Optional Features page to restore the same folder with the same protection. No other changes are required.