Windows 11 does not provide a built-in Settings switch to enable or disable rounded corners across the whole system. An app developer can request a corner style for an individual window through Microsoft’s DWM API, but that is not a consumer setting. Third-party utilities that patch Windows are unofficial, and their compatibility is not established by Microsoft.
What you can change
| Option | Scope | Support status |
|---|---|---|
| Windows Settings appearance options | Colors, accent color, themes, and transparency—not corner geometry | Microsoft-documented appearance controls, but not a rounded-corner toggle |
| DWM corner-preference API | A window controlled by an app that calls the API | Microsoft-documented developer mechanism |
| Third-party DWM patching utility | May attempt to change Windows corner rendering | Unofficial; compatibility and reliability are not established by Microsoft |
Can Windows Settings change rounded corners?
No reviewed Microsoft Windows documentation describes a built-in setting for globally switching rounded window corners on or off. Personalization settings such as accent color on title bars and window borders, themes, and transparency effects change other aspects of appearance; Microsoft does not document them as controls for corner shape. See Microsoft’s Windows color personalization guidance.
| # | Preview | Product | Price | |
|---|---|---|---|---|
| 1 |
|
Windows 11 All-in-One For Dummies, 2nd Edition | $27.49 | Buy on Amazon |
For app developers: set a window corner preference
Desktop app developers can call DwmSetWindowAttribute with the DWMWA_WINDOW_CORNER_PREFERENCE attribute to request a preference for an app window. Microsoft documents this API for Windows builds starting at 22000. It applies to the window whose app makes the call; it is not a way for a user to override every application.
The documented values are:
| Value | Meaning |
|---|---|
DWMWCP_DEFAULT |
Let the system decide whether to round the window corners. |
DWMWCP_DONOTROUND |
Request that the window never be rounded. |
DWMWCP_ROUND |
Request rounded corners when appropriate. |
DWMWCP_ROUNDSMALL |
Request a small corner radius when appropriate. |
See Microsoft’s DWM_WINDOW_CORNER_PREFERENCE reference for the enum definition and applicability details.
#1 Best Overall
What about third-party tools?
The Win11DisableRoundedCorners project describes itself as a utility that patches DWM to disable rounded corners. This is an unofficial approach, not a Windows setting or a Microsoft-supported procedure. The research does not establish that it is safe for every configuration or compatible with current and future Windows updates. Review the project and its risks before deciding whether to use it: Win11DisableRoundedCorners on GitHub.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.FAQ
Can I disable rounded corners everywhere in Windows 11?
There is no built-in, supported Windows Settings switch for changing all windows to square corners. The documented DWM API lets an app request a preference for its own window, not for every application.
Can I use the DWM API to change another app’s window?
The API is documented for an application to set a preference for its window. It is not a general user-facing control for overriding other apps.
Do accent color or transparency settings change corner shape?
Microsoft documents those as appearance controls for colors and transparency, not as controls for window corner geometry.
Quick wins for a faster PC:
Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Repair Windows errors before they cause bigger problemsFix Now →Scan for outdated or missing drivers - takes under a minuteDriver Scan →Is a third-party rounded-corner patch an official Windows feature?
No. A project may describe patching DWM, but that does not make it Microsoft-supported or establish compatibility with your Windows configuration or future updates.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
