How to uninstall Microsoft OpenJDK 21 on Windows

Check JAVA_HOME and the Java version used by existing projects before removing Microsoft OpenJDK 21.

Quit the app

Close Microsoft OpenJDK 21 and any work it is running, then use Task Manager (Ctrl+Shift+Esc) to check for its remaining processes.

Use its uninstaller

Open Settings › Apps › Installed apps, find Microsoft OpenJDK 21 and choose Uninstall. Use the vendor uninstaller rather than deleting its program folder.

winget uninstall --id Microsoft.OpenJDK.21 --exact

For this installation, winget invokes the registered removal method. It is not a separate cleanup of user data. Windows may ask for administrator approval.

Check the result

winget list --id Microsoft.OpenJDK.21 --exact

Read winget's result as well as its exit status: an explicit no-installed-package result concerns only this package, while a source, access or query error leaves the answer unknown. The commands do not delete anything.

What Mole lists

The recorded review contained no extra rows. This does not prove that no data exists elsewhere.

Mole listed no extra rows because the JDK was inside the shared Microsoft program directory. The MSI removed its own JDK directory. Do not remove the Microsoft parent or other installed JDKs.

What this test covered

Recorded on 2026-10-20: Microsoft OpenJDK 21, version 21.0.12.101, machine-wide, MSI, winget package Microsoft.OpenJDK.21. The evidence comes from an ARM64 Windows test environment and a development build of Mole. It does not certify the current downloadable package or removal of real signed-in accounts, synchronized data or production projects.

Vendor documentation. The paths and removal results above are observations from the Windows test unless explicitly attributed to the vendor.