If you suddenly see a message saying “WindowServer experienced a problem” on your Mac, it can be alarming and look like a serious system failure. However, in most cases, the error originates from an app and is temporary. In this article, we’ll explain what WindowServer on Mac is, possible causes of the error, and various options to fix it.
What is WindowServer on Mac?
We run Windows 11 as a virtual machine (VM) on Mac using Parallels Desktop. Because the error appeared while the Windows 11 VM was running, seeing “WindowServer” in the problem report initially made it seem as though the problem was coming from Windows 11 or Microsoft Windows Server. However, “WindowServer” has nothing to do with Microsoft Windows or Windows Server. It is a macOS system process responsible for managing the graphical interface, including application windows, menus, graphics, animations, and other visual elements displayed on the screen.
- Open Finder and navigate to “Applications > Utilities” folder.
- Find and open Activity Monitor app.
- Go to “Memory” or “Disk” tab and click the “Process name” header to sort it alphabetically.
- You should see a process named “WindowServer” runs by the user “_windowserver”.
The error message refers to this WindowServer process or a related component.
Terminating WindowServer Process
Double-click on the WindowServer process in Activity Monitor to open its details and then click “Quit” button to terminate it.
Mac will show a warning that you will be logged out if you quit the process. So, you should not try to terminate the process as it is a core part of macOS.
Also, don’t try to delete the source WindowServer file located in the following location:
/System/Library/PrivateFrameworks/SkyLight.framework/Versions/A/Resources/WindowServer
Should I Click “Send to Apple”?
When WindowServer crashes, macOS displays a Problem Report as shown below with the options for “Show Details”, “Don’t Send”, and “Send to Apple”.
If you want to investigate the problem yourself first, click “Show Details” and examine the report. The most useful information is often the process name, crash type, exception information, and details about what was running when the crash occurred. In most case, you don’t need to send the details to Apple (unless you are discussing with the official Apple support team) as it may contain sensitive information.
Why Does WindowServer Crash?
In our case, the problem was triggered by Snagit, a screen capture application. Because Snagit interacts with the Mac’s screen and graphical interface, a problem with the application can cause an issue involving macOS’s WindowServer process. However, the root cause may vary based on the situation and here are some common possible causes:
- An outdated version of the app or macOS.
- A third-party application that interacts heavily with the graphical interface like screenshot, screen recording or window management utilities.
- External monitors, USB-C or Thunderbolt accessories.
- Third-party system extensions, login items or background applications.
- Corrupted system or application data.
- A hardware problem.
If you saw the message once and everything is working normally afterward, you generally don’t need to perform extensive troubleshooting. A practical approach is to just follow the basic troubleshooting steps listed below. Try other steps if the issue happens repeatedly.
1. Basic Troubleshooting Options
Start with these basic steps before moving on to the advanced options.
- Restart your Mac: The simplest solution is to restart the Mac by going to “Apple menu > Restart”. After restarting, use the Mac normally and see whether the message appears again.
- Update macOS: An outdated macOS installation can contain bugs that affect system processes. Go to “Apple menu > System Settings… > General > Software Update” and install any available macOS updates.
- App Updates: If the problem happens every time you open a particular application, update that application first. Go to “App Store > Updates” to update the apps installed from App Store. For third-party apps, get the updates through the app or from the developer’s website. If an update is unavailable, temporarily uninstall it and test the Mac.
If the issue keeps happening, continue with the following steps.
2. Check External Devices
WindowServer is heavily involved in displaying graphics, so an external display or device deserves special attention.
- If you have a monitor connected, try using the Mac without it for a while.
- Temporarily disconnect USB hubs / drives, docking stations, Thunderbolt devices, display adapters, printers, and speakers.
- Then restart the Mac and use it normally.
- If the crash stops, check the device’s connection, related software installed, USB-C or Thunderbolt cable, display adapter, dock, and firmware.
- Reconnect the devices one at a time to identify which device or adapter is causing the problem.
If you use utilities that modify how multiple displays work, also temporarily disable or uninstall them to determine whether they are involved.
3. Start your Mac in Safe Mode
Safe Mode is one of the most useful ways to determine whether third-party software is involved. The procedure is different depending on whether your Mac has Apple silicon or an Intel processor.
Apple silicon Mac:
- Shut down the Mac.
- Press and hold the power button until “Loading startup options” appears.
- Select your startup volume.
- Hold the Shift key and click “Continue in Safe Mode” to login.
- You should see “Safe Boot” in the menu bar or check the “Boot Mode” in System Information app under “Software” section.
Intel Mac:
- Shut down or restart the Mac.
- Immediately press and hold the Shift key.
- Continue holding it until the login window appears and login to your Mac.
- “Safe Boot” should appear in the menu bar.
Use the Mac in Safe Mode for a while. If the WindowServer problem does not occur in Safe Mode, that is a useful clue that third-party software, extensions, login items, or other startup components may be involved.
4. Check Login Items
An application that launches automatically when you sign in can cause problems repeatedly.
- Go to “Apple menu > System Settings… > General > Login Items & Extensions”.
- Look at the applications listed under “Open at Login” and background activity.
- Temporarily remove suspicious or recently installed applications from the startup list.
- Restart the Mac and check whether the problem returns.
5. Remove Problematic Background Apps
Some applications continue running even when their main window is closed. This is especially common with window managers, display utilities, remote access software, screen capture apps, and system monitoring tools.
- Go to “Apple menu > System Settings… > General > Login Items & Extensions”.
- Check under “Background App Activity” section.
- Disable unnecessary apps in the list.
6. Run Disk Utility First Aid
If the problem continues, you can check the startup disk using Disk Utility.
- Go to “Finder > Applications > Utilities” folder.
- Find and open “Disk Utility” app.
- Select the appropriate volume and click “First Aid” from top toolbar.
- Confirm your action by clicking “Run” button.
Disk Utility can check storage devices and repair certain disk or volume errors thus helping to fix the issue.
7. Run Apple Diagnostics
If you suspect that the problem might be hardware related, Apple Diagnostics can check the Mac’s internal hardware.
On an Apple silicon Mac:
- Shut down the Mac.
- Press and hold the power button.
- Continue holding until the startup options screen appears.
- Release the button and press Command + D.
On an Intel Mac:
- Shut down the Mac and then turn it on.
- Immediately hold the D key.
- Follow the instructions on screen.
Apple Diagnostics can help identify problems involving internal hardware. If Diagnostics reports an error code, record the code before contacting Apple or a service provider.
What if it Keeps Happening?
Repeated WindowServer crashes should not simply be ignored. If the Mac continues crashing after the above mentioned troubleshooting steps, particularly if Apple Diagnostics reports a hardware problem, contact Apple Support or an authorized service provider for fixing the issue.
