Lance Whitney / Elyse Betters Picaro / ZDNETWindows 10 and Windows 11 users who installed last week’s April Patch Tuesday updates may have noticed a strange new folder appear on their system drive, or C drive. Also: 10 pesky Windows 11 24H2 bugs still haunting PCs despite several patchesNamed “inetpub,” the folder is associated with Microsoft’s IIS (Internet Information Services), a component for hosting a website on your PC. If you do not use IIS, you may think the new folder is unnecessary and simply delete it. Not so fast.Leave it aloneThe new folder is needed, though not for IIS. Instead, it is part of a security fix designed to squash a bug that could leave your PC vulnerable to attack. Specifically, the CVE-2025-21204 security flaw involves a scenario in which symbolic links are not handled properly and, therefore, could be exploited by an attacker to access or modify certain files and folders. Also: How to replace your Windows 11 Start menu with a better alternative – including my favoriteThat certainly sounds like a glitch that needed to be patched. The problem is that Microsoft failed to communicate why the inetpub folder was added. That led to confusion among Windows users and likely prompted many to delete the folder, thinking it had been created by mistake. To address the confusion, Microsoft told Windows Latest that users should not remove the folder. The company also updated its advisory to clarify the purpose of the folder. Also: Windows 11 is getting a secret weapon for boot failures – how it works”After installing the updates listed in the Security Updates table for your operating system, a new %systemdrive%inetpub folder will be created on your device,” Microsoft said. “This folder should not be deleted regardless of whether Internet Information Services (IIS) is active on the target device. This behavior is part of changes that increase protection and does not require any action from IT admins and end users.”If you see the inetpub folder in Windows, just leave it alone. More