Kindly try the following steps :
To turn on, or turn off screen rotation, swipe in from the right, select PC Settings and look for the Screen icon. Tap the Screen icon and you will see a vertical slide control for brightness. At the top of the brightness control you will see a rectangle, representing a screen, with a curved arrow at the lower right corner. Tap the rectangle once to lock the screen rotation in the current position, portrait or landscape. The curved arrow will change to a lock. To unlock screen rotation, follow the same procedure, tap the rectangle with the lock and it will change back to the curved arrow.
Please update drivers and check if issue persists. If the button has disappeared and issue is not resolved after updating driver, reset the operating system after backing up data. Confirm if this helps.
I wasn't clear enough. The issue isn't the status of the "Lock rotation on this display" slider.
That slider disappeared (along with the related "notification action" button) with the update too.
One can restored those UI items by adding: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersionAutoRotationSensorPresent=1 to the registry.
The problem is that, after the update, the tablet appears to have lost the feature of being able to "auto rotate".
Download Chipset driver on the tablet on a different location. Please uninstall and install Chipset driver.
Goto Control Panel (view by large icons to see all items) | Tablet PC Settings | 'choose the order in which your screen rotates [go to orientation] '.
Change the sequence to the following:
1) Primary portrait
If issue persists, refresh the operating system after backing data and check if you are getting the Slider with auto-rotation.
What I think causes the problem is the order of updates (Windows and chipset driver).
This is the "nuclear option" because you have to restore the tablet.
What fixed the problem for me.
1) Restore/reset the tablet. When the initial Windows setup screen appeared, the touch didn't work (!!). I connected a USB keyboard and mouse and continued with the install. I used an Apple USB C to USB A (female) adapter that currently costs $9. After awhile, the touch screen started working and so did screen rotation. (It was disconcerting to have the touch not work; I don't quite get how it started up again).
2) Once that finished, changed the wifi connection to "metered". This keeps Windows from pushing updates. Click on the WIFi icon and select your current connection. Click on "properties" and turn "Metered Connection" to "on". (You can turn this off after you finish getting the tablet updated.)
3) Update the chipset driver (1/29/2016/261,6MB is the latest one. The Realtek Audio Driver for Dell Wireless Dock (3/18/20126), Realtek USB GBE Ethernet (1/21/2916), was also updated. The screen autorotation still worked.
4) Find the latest Windows 10 cumulative update. support.microsoft.com/.../3200970 (11/8/2016). I'd suggest using "Method 2: Microsoft Update Catalog". This approach gives a better indication of what is being done and the progress of the update than the standard Windows Update process. Once the 800MB file is downloaded, run the file. This takes a long while to run. The screen autorotation still worked.
5) You may want to run "Disk Cleanup" afterwards (also click the "Clean up system files" button at the bottom before clicking "OK"). Select the "Windows Update Cleanup" checkbox in the list displayed.
6) Windows Update might also need to be cleaned-up (especially, it it's really slow). If total size of files in c:\Windows\SoftwareDistribution is large, you might want to clean it out. NOTE: Doing this will delete the update history. You'll need to boot into safe mode.
6.1 Boot into safe mode (for tablets).
Run msconfig.exe and change the boot attributes to boot the tablet into safe mode.
6.2 Cleaning c:\windows\SoftwareDistribution