Screen resolution.

Hi everyone,

I have a MacBook Pro 15" and at home usually connect it to an external Monitor so to use it's monitor and the external as well. But some times it looses the resolution setting on the external monitor and becomes very low resolution and also the desktop background changes as the resolution changes. I now disconnected and reconnected the thunderbolt connection and the good resolution came back together with the selected background.

Can anyone help about this because it is the second time that happens.

Thanking you in advance

If you "mirror" the external display and keep the lid on your MBP open at the same time, the external monitor will use the same resolution as your MBP.

In order to use the external monitor at its native resolution, you must close the lid on your MBP and use mirror mode. Keeping the lid closed will require an external keyboard and mouse and is known as "clamshell mode". See the following Apple KB article: LINK

Hi thanks for your reply,

I use the external monitor as an extended monitor so to have 2 monitors at the same time. Is this allowed?

The most of the time the resolution is good. But suddenly the resolution turns low did it twice in 2 months. can it be because the mac was on battery?

Thanks again

I use the external monitor as an extended monitor so to have 2 monitors at the same time. Is this allowed?

Click to expand...

Sure, lots of folks use that. It's called extended desktop mode.

But suddenly the resolution turns low did it twice in 2 months. can it be because the mac was on battery?

Click to expand...

LOL, of course. You can't expect your MBP to provide a video signal strong enough to drive an external monitor when it's on battery. Apple cautions against doing that by the way. You need to be operating from the AC mains.

Have fun.

Thanks again for your reply.

Because I was beginning to be worried.

Thanks again.
Regards

lol - did the same thing.

My MBP is always connected to power when I use a monitor with it.

Just tried using my MBA with an external monitor for the first time a couple weeks ago - took me a few to figure out it wasn't going to work on battery.

lol thanks for all your help. I am new to such things so happens. Thanks again