Yes, that's what i mean. 

This is what i already did, but unfortunately does not work for me. 

I have Win 10 Pro 64 Bit and upgraded directly  from win 8.1 pro 64 Bit. Before the migration i had Start8 installed, also there it did not work under Win 10. Now i upgraded to Start10 because i hoped that then it will work but it did not. 

When i deinstall Start10 it works, after installing it again and activate auto-hide, it hides one time but then stays permanent. 

Win10 has all latest updates installed. 

Any ideas? 

This evening i found out myself what caused the problem.

So now the solution of the problem:

After stopping the application of taskbaricon with the name „Common Software Manager“ from „Flexera Software LLC.“ the autohide of the taskbar worked again.

This is installed autmatically  with some products of the company „Nuance“, it checks for available updates of the software from Nuance.

To permanently fix it i just deactivated the above named program in autostart. This could be achieved by right click on the taskbar, choose „Task-Manager“, then click on „Autostart“, right click again on the named application and choose „deactivate“.

As i would not realy miss this app, for me this is a permanent fix.

If you do not use this app and have also the same issue, it would also be helpful to stop apps in the taskbar, one after each other, and see if it solves the problem, as other apps my also cause such behaviour.