DeX Auto Start on HDMI Connection launches screen mirroring instead of DeX mode

Environment

• Knox Service Plugin
• EMM
• Samsung DeX
• Android 16 devices running One UI 8.0

Overview

On devices running Android 16 OS with One UI 8.0, the DeX Auto Start on HDMI Connection feature in Knox Service Plugin may not work as intended. Instead of automatically launching DeX mode when you connect an HDMI cable, your device starts screen mirroring.

This issue affects both:

• Newly enrolled devices running Android 16 OS with One UI 8.0 firmware (including out-of-box devices going through the Galaxy Setup Wizard or factory-reset devices enrolling into an EMM as a device owner).
• Existing devices that’ve upgraded from Android 15 to Android 16 with One UI 8.0.

Cause

When enrolling devices into EMMs or performing OS upgrades on Android 16 devices with One UI 8.0 firmware, the DeX Auto Start on HDMI Connection policy may fail to apply due to database changes made during the Android Setup Wizard process.

As the Android Setup Wizard runs in both the initial device setup process (out-of-box or factory-reset devices), and after an OS upgrade, both new device enrollments and devices with recent firmware upgrades can experience this issue.

Resolution

This issue is resolved with One UI 8.5. We recommend you update your device firmware.

Workaround

As a temporary workaround, you can resolve the DeX Auto Start issue by either:

• Rebooting your device after connecting the HDMI cable.
• Tapping the DeX icon in Quick Panel to switch from screen mirroring to DeX mode.