WPF applications might not work correctly if an IME is used

Summary

After you install Windows updates released on or after June 25, 2024, applications which are built on Windows Presentation Foundation (WPF) might experience issues when you use certain Input Method Editors (IME), including Japanese.

WPF applications might stop responding or close unexpectedly if an IME is in use when inputting characters into application fields. Some actions may cause this issue to occur more easily, such as when characters are typed quickly or when the IME produces additional input dialog boxes. Since there is a timing element to this issue, it may not occur consistently. Slow input of characters might help reduce the likelihood of encountering this issue. 

Resolution

This issue is resolved in the Windows updates released on or after December 10, 2024:

• For Windows 11, version 22H2 Windows 11, version 23H2: December 10, 2024—KB5048685 (OS Builds 22621.4602 and 22631.4602)

• For Windows 11, version 24H2: January 14, 2025—KB5050009 (OS Build 26100.2894)

• For Windows Server 2025: January 14, 2025—KB5050009 (OS Build 26100.2894)

Temporary workaround

This issue is addressed by a Known Issue Rollback (KIR), which can temporarily work around this issue by using a special group policy.

To apply the KIR group policy to a single device, follow these steps:

1. Download the following KIR policy definition MSI (.msi) file to a folder on your device such as the Downloads folder:
   
   Download the KIR policy definition .msi file

2. Double-click to run the .msi file (Windows 11 24H2 and Windows Server 2025 KB5040435 241022_20351 Known Issue Rollback.msi) on the device. Follow the prompts in the installer to install the KIR policy definition under Administrative Templates in the Local Group Policy Editor.

3. Open the Local Group Policy Editor. To do this, select Start, type gpedit.msc. in the Search box, and then select Edit group policy.

4. Under Local Computer Policy, expand Computer Configuration > Administrative Templates > KB5040435 241022_20351 Known Issue Rollback, and then select Windows 11 24H2 and Windows Server 2025.

5. Under Settings, right-click the KB5040435 241022_20351 Known Issue Rollback policy, select Edit > Disabled, and then select OK.

6. Close the Local Group Policy Editor, and then restart the device.

For information about deploying and configuring this special group policy in a hybrid Microsoft Entra ID or AD DS domain, see  How to use Group Policy to deploy a Known Issue Rollback.