Aumentar y disminuir tamaño y dureza del pincel con atajo

For the majority of Mac users the Control + Option left click and drag side to side for size and up/down for hardness

works or there would be many reports here on the forums that it doesn't.

Do you have a laptop?

You can try a Photoshop preferences reset and see if that makes any difference:

https://helpx.adobe.com/photoshop/using/preferences.html

Any news?

NEWS:

The CTRL button doesn't work while using the brush, it works right if I do other shortcuts like save as a copy, but not with the brush.

I've changed the function button CTRL to FN on preferences and I'm able to use the shortcut. Does anyone could know why is it bugging me?

But

Any solution?

On a Mac it's Control Option left click and drag side to side for size and up/down for hardness.

What occurs if you press the Opt key and the right mouse button at the same time? I can modify the hardness on Windows by using Alt + right mouse button or by pressing Ctrl + Alt + right mouse button and dragging upward or downward.

@marcbichi 

I've moved your post from Creative Cloud Desktop to the Photoshop forum for you.

Instead of "latest", what is your exact version of Photoshop (Help menu > System Info) and your OS?

Jane