How to fix “Class still has open windows. [ERROR_CLASS_HAS_WINDOWS (0x584)]” – Error Code 1412


Error Code 1412

Error code Error Code 1412 is a common Windows issue that typically arises from “Class still has open windows. [ERROR_CLASS_HAS_WINDOWS (0x584)]”.


In this article, we’ll focus on resolving the issue described as: “Class still has open windows. [ERROR_CLASS_HAS_WINDOWS (0x584)]”. This error, identified by the error code Error Code 1412, can impede your system’s performance, and here’s how you can fix it.

Identifying the Problem

What is Error Code 1412?

Error Code 1412 is a Windows operating system error code that indicates that a class of objects still has open windows. This error typically occurs when an application attempts to close or terminate, but there are still windows associated with that class that remain open.

Typical Scenarios

Error Code 1412 may appear in various scenarios, including:

  • When closing an application that has multiple open windows
  • When shutting down Windows while applications are still running
  • When attempting to install or update software

Signs of Error Code 1412

The following signs may indicate that you have encountered Error Code 1412:

  • An error message stating “Class still has open windows” or “Error Code 1412”
  • Difficulty closing applications
  • Inability to shut down Windows properly
  • Software installation or update failures

Common Fixes

Close All Open Windows

The simplest solution for Error Code 1412 is to close all open windows associated with the affected class:

  • Right-click the application’s icon in the taskbar.
  • Select “Close all windows” or similar option.
  • After closing all windows, try to close the application or perform the action that was triggering the error.

End Processes Using Task Manager

If closing windows manually does not resolve the issue, use the Task Manager to end the application’s processes:

  • Press Ctrl+Alt+Delete and select “Task Manager”.
  • Under the “Processes” tab, find the application’s process.
  • Right-click on the process and select “End task”.
  • Repeat for all related processes until none remain.

Restart Windows

Restarting Windows can sometimes clear up system errors, including Error Code 1412:

  • Click Start and select Power > Restart.
  • Allow Windows to restart fully and then try to perform the action that was causing the error.

Advanced Troubleshooting

Use Process Explorer

Process Explorer is a tool that provides more detailed information about running processes:

  • Download Process Explorer from Microsoft.
  • Run Process Explorer and locate the application’s process.
  • Expand the process tree to identify all related processes.
  • End all related processes using the “Kill Process Tree” option.

Update or Reinstall Applications

Outdated or malfunctioning applications can cause Error Code 1412:

  • Update the affected applications through the Windows Store or application settings.
  • If updates do not resolve the issue, consider reinstalling the applications.

Check for System Updates

System updates can include bug fixes that address issues like Error Code 1412:

  • Go to Settings > Update & Security > Windows Update.
  • Check for and install any available updates.


By following the steps outlined in this article, you should be able to resolve Error Code 1412 effectively. Remember to close open windows, end processes using Task Manager, restart Windows, and explore advanced troubleshooting options if necessary. By implementing these solutions and maintaining your system’s integrity, you can prevent future occurrences of this error and ensure smooth system operation.