Hi Have you tried the following

If you wish to make your mouse scroll horizontally Press SHIFT and then use the Middle mouse scroll wheel. This works if the page is large enough to be scrolled horizontally. You could see a scroll bar at the bottom.

On Windows 10

'press wheel down once'

- works for me. (Excel & Mingle web page)

so should I say TY for the tip?

Have you tried going to the mouse manufacturers web site and looking for updated drivers?

Another thing you could try is to shut down the computer then plug the mouse into a different usb port and start the computer and it should redetect the mouse on start up,

Funny, you say vertical scroll button is there.

Then it's not possible to lose horizontal scroll in Windows 10, as per control panel.

When I go to control panel then mouse in the mouse properties window is a wheels tab. Is that what you are trying to find?

The Wheels tab ONLY offers a choice to scroll a certain amount of lines, vertical or horizontal
and NOTHING else.

(New mouse)
Is it possible your old mouse had a side scroll feature which scrolled horizontally by tilting the wheel sideways? (I've had such a mouse before)

My current mouse does not have such a feature, it rolls and clicks but no side scroll tilt.
In order for me to get side scroll I must first click down on the wheel till the cursor turns to a circle with a dot and two arrows, then I move my mouse for auto scroll vertical or horizontal, click the mouse again to exit auto scroll.
I use auto scroll to read large volumes of text.

The side tilt wheel can usually be found on a multi-function gaming mouse.
It can also be found on basic+ mouse models which are usually included in the higher end manufacturer computers (Tower/Mouse/Keyboard)


See the arrows next to the wheel?


Common mouse properties when mouse is equipped.

To figure out if there is a mouse or settings problem, first look to see if there are two little arrows next to the mouse wheel.
If so, see if you can push the wheel sideways each direction (you should feel definite movement in each side direction).
If so, check the property box for side scroll settings in the control panel.
Or...
Go to Control Panel (Show Icons)>Device Manager:
Scroll down to Mice and other pointing devices and click the little arrow next to it.
It should show your mouse or mice in a pulldown list.
Rt Click your mouse and select update drivers or choose properties then find drivers tab and choose update drivers.
Let windows search for new drivers, then follow the screen prompts.

Think of hardware drivers as the engine that makes the hardware run. Many times there are multiple drivers for each hardware and often different hardware share the same drivers.

If the mouse is equipped with a side scroll wheel and updating drivers doesn't work you can try a driver rollback or uninstalling the device then unplugging the mouse and plug it back in to let windows install the drivers.

What likely happened is your old mouse had a side scroll wheel but your new mouse does not.
If that is the case, you can buy a side scroll mouse to test that theory (they are not really expensive). Just look for the little arrows near the wheel before you buy it. <|>