Hi DF,
You're definitely not alone in this many Surface Pro 9 users have reported that the "Tablet" option is missing from their Settings, and that their device doesn't switch to tablet mode even when the keyboard is detached. This issue has been discussed across Microsoft’s Q&A forums and Reddit, and it appears to be tied to how Windows 11 now handles tablet functionality. Unlike Windows 10, Windows 11 no longer includes a manual toggle for Tablet Mode. Instead, it’s supposed to automatically switch to a touch-optimized interface when the keyboard is removed or folded back. However, several users have found that this automatic switch doesn’t always work as expected. Some have noted that the device detects the keyboard removal (as seen in Device Manager or the Surface app), but the UI doesn’t respond accordingly. Others have tried workarounds like restarting the device, putting it to sleep and waking it up, or even uninstalling the Type Cover driver manually to force the switch. It's also worth checking for the latest Windows updates, and some try to update the surface app and if the problem continues, you might consider reporting it directly to Microsoft Support to help escalate the issue.
Useful Links
https://appuals.com/cant-enable-tablet-mode-windows-11/
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Best,
Carl