Unable to scroll MacBook Air screen with Arrow Keys

Is this a new problem on that Mac?

Maybe there's something helpful in this earlier thread on the subject: Scrolling with arrow keys doesn't work Ma… - Apple Community

Have you restarted your Mac lately?

If a simple reboot of your Mac doesn’t fix things, see if the problem still happens in safe mode.

How to use safe mode on your Mac - Apple Support 

Safe mode will often correct weird software behavior by forcing the OS to do disk repair, clear caches and other housekeeping and temporarily disables third-party mods. When you're in safe boot, the machine won’t be at its best performance, especially with graphics, but that's expected.

Does the same thing happen while in Safe mode?

You can exit safe mode by restarting your Mac normally.

mrminnehan Said:

"Unable to scroll MacBook Air screen with Arrow Keys: arrow keys not scrolling up or down"

-------

If You Can't Scroll with Arrow Keys:

What's the app you are using? Some apps just don't let you scroll. As for getting it to be scroll, be certain you have clicked the app to get it active.