Rounded Corners Not Working in Windows 11? How to Check and Fix Square Corners

If your Windows 11 windows have square corners, first double-click the window’s title bar to restore it, because maximized and snapped windows are square by design. If every restored window is still square, check your graphics driver in Device Manager (Fix #1 below). Microsoft’s other documented exceptions include some custom app frames and virtual machines or Azure Virtual Desktop sessions, and the quick check below rules those out before you change settings. The visual change from Windows 10 or a question about a Remote Desktop session does not establish a cause on your PC.

Quick Check: Is It Actually Broken?

Windows 11 applies system-rounded corners to its built-in apps and most other top-level app windows. Some customized Win32 windows are exceptions. Windows also keeps corners square by design in some situations, so check these before you change anything:

• Confirm you’re on Windows 11 by going to Settings > System > About. This guide concerns Windows 11’s system window-rounding behavior, not custom corners drawn by individual apps.
• Restore the window by double-clicking its title bar. Maximized and snapped windows have square corners by design. Microsoft’s geometry guidelines (retrieved 2026-10-04) say Windows doesn’t round windows that are maximized or snapped.
• Drag the window away from the screen edge and check the corners again.
• Check whether it’s every window or just one. If one app is square and the rest are rounded, skip to the FAQ. That’s an app choice, not a Windows fault.
• Restart your PC if you haven’t since the corners changed.

If every restored window is still square, work through the fixes below in order.

Symptoms and Likely Causes

Symptom	Likely Cause	Fix to Try
All corners square right after a driver or Windows update	Possibly a missing or broken graphics driver (worth ruling out, not a documented cause)	Fix #1
Corners went square after you tweaked performance settings	Possibly the changed effects (not a documented cause)	Fix #2
Corners square for no obvious reason	Unknown; a fresh session is a simple test	Fix #3
Corners square after using Remote Desktop	Unconfirmed; signing out is a simple test	Fix #4
Nothing above helped	Unknown; rule out pending updates and file corruption	Fix #5
Only one app is square	App’s custom window frame or opt-out	FAQ
Square inside a VM or Azure Virtual Desktop	Virtual display limitation	FAQ

Fixes for Square Corners in Windows 11

Microsoft documents the by-design cases in the quick check and FAQ, but it doesn’t document a specific cause for square corners on an ordinary restored window. The steps below are low-risk checks ordered from quickest to most time-consuming, not by how likely each is to be the cause, and none is a guaranteed fix.

Fix #1: Update or Reinstall Your Graphics Driver

Rounded corners are drawn by Desktop Window Manager (DWM). Microsoft doesn’t document a graphics-driver problem as a cause of square corners on ordinary restored windows, so treat this as an editorial troubleshooting step: if the corners changed right after a driver or Windows update, checking which display driver is loaded is quick and low-risk. In one Microsoft Q&A thread on missing round corners (retrieved 2026-10-20), square corners inside a VMware virtual machine came back after the poster rolled back a VMware update, which points to the virtual display driver in that one case; it doesn’t prove the same cause on a physical PC.

• Right-click the Start button and select Device Manager.
• Expand Display adapters.
• Check the name of your graphics adapter. If it says Microsoft Basic Display Adapter on a physical PC, Windows is using its generic display driver instead of your GPU maker’s driver. (In a virtual machine or some remote sessions a generic or virtual adapter is normal.)
• Right-click the adapter and select Update driver.

• Select Search automatically for drivers and let Windows install what it finds.
• Restart your PC.
• Open Device Manager again and confirm the adapter now shows your GPU’s real name (NVIDIA, AMD, or Intel).

If Windows can’t find a driver, laptop and prebuilt-PC owners should start with the PC maker’s support page, because many of those systems use a customized driver package and a generic driver (especially a clean install) can remove maker-specific components. On a desktop with a separate graphics card, download the latest driver from NVIDIA, AMD, or Intel.

Verify it worked: Restore a window and check the corners after the restart. If they’re still square, move on to the next check. One test doesn’t fully rule the driver out, but further driver changes are unlikely to be worth the effort.

Tip: A yellow warning icon on the adapter with “Windows has stopped this device because it has reported problems. (Code 43)” can mean a driver problem or a failing graphics card. Code 43 alone doesn’t prove the hardware is failing. Try reinstalling the driver from your PC or card maker first. If the error persists, contact the PC maker’s support, or on a desktop with a separate card, have the card tested before deciding whether a graphics card upgrade makes sense.

Fix #2: Turn Transparency and Animation Effects Back On

Microsoft’s rounded corners documentation doesn’t list Transparency effects, Animation effects, or the Adjust for best performance preset as controls for window rounding (checked October 20, 2026). Treat this as a quick, reversible check rather than a known fix, and only bother if the corners went square around the same time you changed these settings.

• Open Settings > Personalization > Colors.
• Turn on Transparency effects.

• Go to Settings > Accessibility > Visual effects.
• Turn on Animation effects.

• Press Win + R, type SystemPropertiesPerformance, and press Enter.
• Select Let Windows choose what’s best for my computer if you previously chose Adjust for best performance, then click OK.
• Sign out and back in.

Verify it worked: Open File Explorer, restore it to a normal size, and check the corners. If they’re still square, these settings probably aren’t the issue; set them however you like and move on.

Fix #3: Save Your Work and Sign Out

If you want to start a fresh local session, use Windows’ normal sign-out action. This is a general session check, not a documented cure for square corners or proof that DWM failed. We don’t give a way to restart DWM directly because Microsoft doesn’t document a supported method for ordinary users; signing out (or restarting) is the safe way to get a fresh desktop session. Microsoft’s sign-out guidance warns that open apps close and unsaved work may be lost.

• Save your work and close your apps.
• Open Start, select your user picture or Accounts icon, then select Sign out.
• Sign in again and compare the same restored window.

Warning: Don’t try to “restart” Desktop Window Manager by ending it in Task Manager. It’s a protected Windows process, and ending it isn’t a supported restart method; it can leave you with a black screen. The screenshot below shows the Task Manager End task option on Desktop Window Manager so you can recognize it and avoid it; it is not a step to perform.

Verify: If the corners are rounded again, the fresh session helped, though that doesn’t show what caused the problem. If they’re still square, this reset simply didn’t help; continue with the next fix.

Fix #4: Fully Sign Out After a Remote Desktop Session

If you connected to this PC remotely and the corners are square when you sit down at it, a full sign-out starts a fresh local session. We haven’t found Microsoft documentation linking Remote Desktop to square corners on the local session, so treat this purely as a quick test.

• Save your work and close open apps.
• Click Start, then click your profile picture.
• Select Sign out. Locking the PC or closing the Remote Desktop window usually leaves the session running in a disconnected state rather than signing it out (the exact behavior depends on how the PC is configured), so use Sign out.
• Sign back in at the PC itself.

Verify: Check a restored window after you sign back in. If the corners are still square, this reset didn’t help; that doesn’t rule Remote Desktop in or out, so continue with the next fix.

Fix #5: Run Windows Update, DISM, and SFC

If nothing else worked, rule out pending updates and system file corruption. This is general Windows maintenance rather than a documented fix for corners. It needs administrator access, and the scans can take a while, so keep the PC plugged in until they finish.

• Go to Settings > Windows Update.
• Click Check for updates and install the updates offered. Under Advanced options > Optional updates, install only a display-driver update for your graphics adapter, if one is listed; skip unrelated optional drivers.

• Restart your PC.
• Click Start, type cmd, right-click Command Prompt, and select Run as administrator.
• Run DISM /Online /Cleanup-Image /RestoreHealth and wait for it to finish. This repairs the Windows image that SFC uses as its source.
• Run sfc /scannow and wait for it to reach 100%.

• Restart your PC.

Verify it worked: Restore a window after the restart. For more detail on reading the scan results, see our guide to fixing corrupted files with SFC and DISM in Windows 11.

Error Messages You Might See

Message or Status	What It Means	What to Do
“Microsoft Basic Display Adapter” in Device Manager	Windows is using its generic driver rather than your GPU maker’s (normal in many VMs)	Fix #1 on a physical PC
“Windows has stopped this device because it has reported problems. (Code 43)”	Windows stopped the device after it reported a problem; the cause could be the driver, firmware, configuration, or hardware	Reinstall the driver from your PC or card maker first; contact support if it persists
“Windows Resource Protection did not find any integrity violations.”	System files are fine	Corners aren’t a file problem; recheck Fixes #1 to #4
“Windows Resource Protection found corrupt files and successfully repaired them.”	SFC fixed something	Restart and check the corners
“Windows Resource Protection found corrupt files but was unable to fix some of them.”	Repair is incomplete	Run DISM again, then SFC again
“The restore operation completed successfully.”	DISM repaired the Windows image	Run sfc /scannow next
“Error: 0x800f081f The source files could not be found.”	DISM couldn’t download repair files	Check your internet connection and Windows Update, then retry

If You Actually Want Square Corners

Some people prefer square corners. Before you troubleshoot, check that nobody else who uses this PC made that change on purpose.

We couldn’t find an option in Settings or a Microsoft-documented way to turn off rounded corners for all windows; Microsoft’s rounded corners documentation covers only a preference that app developers set for their own windows. Your options are limited:

• Registry tweaks you find online (for example, values named RoundedCornerOverride) aren’t documented by Microsoft. Many don’t work on current builds, and some only worked on early previews. Treat them as unsupported.
• Forcing the Basic Display Adapter is sometimes suggested online, but it isn’t a documented way to square corners, and it replaces your graphics card maker’s driver with Windows’ generic one, so features you rely on for games, video, or multi-monitor setups may not work as well. It’s not worth the trade.
• Third-party tools that modify Desktop Window Manager exist, but Microsoft doesn’t support them and we don’t recommend them; changes to a core Windows process are hard to undo or troubleshoot if something goes wrong.

If none of these trade-offs suit you, maximizing or snapping windows gives you square corners with zero risk.

Getting Help

If the corners still won’t come back, gather this information before you post on Microsoft Q&A or contact your PC maker:

• Your Windows version and build from Settings > System > About
• Your graphics adapter name and driver version from Device Manager > Display adapters > Properties > Driver
• Display errors in Event Viewer > Windows Logs > System (look for “Display” or “nvlddmkm”/”amdkmdag” sources)
• The SFC log at C:\Windows\Logs\CBS\CBS.log
• The DISM log at C:\Windows\Logs\DISM\dism.log

Prevention Tips

• Keep track of your GPU driver source: Windows Update and vendor driver packages normally coexist, but if you install a driver manually, note where it came from so you can roll back or reinstall the same package if problems start.
• Sign out after remote work: If you use Remote Desktop to reach your own PC, sign out fully before using it locally.
• Protect updates from power loss: A power cut mid-update can corrupt drivers and system files. A UPS (uninterruptible power supply) can keep a desktop PC running through short outages, which reduces (but doesn’t eliminate) that risk.
• Create a restore point before tweaks: Do this before trying any registry edit so you have a way to roll back.

Help & Answers

Frequently Asked Questions

2 questions

Why is only one app showing square corners?

Developers can tell Windows not to round their app’s windows using a setting called DWMWCP_DONOTROUND, as described in Microsoft’s rounded corners documentation (retrieved 2026-10-04). The same page explains that apps with heavily customized window frames may not be rounded automatically, and apps that use per-pixel alpha layering or window regions can’t be rounded at all. Updating the app may help, but you can’t change this from Windows settings.

Why are corners square in a virtual machine or Azure Virtual Desktop?

Microsoft’s rounded-corners documentation lists virtual machines, Azure Virtual Desktop sessions, and Windows Defender Application Guard windows as cases that are not rounded by design. It does not establish missing GPU acceleration as the cause or recommend extra video memory as a corner-rounding fix. Do not change those resources solely to make corners round.

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Wrapping Up

Most square corners turn out to be by design, so restore the window and check other apps before changing anything. If you also see Code 43, screen artifacts, or random black screens, treat that as a graphics driver or hardware problem worth fixing in its own right.

Step	Action	Applies To
Quick check	Restore window, check other apps, restart	Everyone
Fix #1	Update or reinstall GPU driver	Square after updates
Fix #2	Turn on transparency and animation effects	After performance tweaks
Fix #3	Save work and sign out normally	Optional fresh-session check
Fix #4	Fully sign out and back in	After Remote Desktop
Fix #5	Windows Update, DISM, SFC	Nothing else worked

Last updated: October 20, 2026 | Applies to Windows 11 Rounded Window Corners (Desktop Window Manager) on Windows 11