External Monitor Color Depth

[Apples555]

I have a second monitor connected through the mini-displayport on my MacBook Pro.

If I start the computer from off, everything is fine. But if I plug in the monitor while the computer is on or sleeping, everything is fine except the color depth of the external monitor is significantly reduced. Color banding is visible.

If this occurs, restarting the computer will fix it. As I mentioned, if the monitor is plugged in before the computer boots, all is well.

This doesn't occur in Windows 10, only in Sierra.

How do I circumvent this? There is no color depth option in preferences as far as I can tell.

 

[Sanpete]

Sometimes it matters in what order the cable is connected to which machine (i.e. monitor first or MBP first), so you try it in whatever order you haven't tried yet.

 

[Apples555]

Monitor is old VGA so is connected through an adapter to MDP.

 

[Sanpete]

Try various orders of connecting the connectors, including the adapter, then. (Unless someone comes up with a better idea!)

 

[Apples555]

Doesn't seem to have an effect. Only get full color depth if computer started cold.

 

[Sanpete]

I haven't heard of anything quite like this. Have you talked to Apple? They'll want you to reset stuff and maybe boot in safe mode, maybe even do a clean install, which isn't a bad idea anyway. But ultimately if you persist it will reach the ears of an engineer who might be able to say something useful about it.

Or you could file a bug report, but that might not help you any.

 

[Apples555]

I can file a bug report, but I'd be surprised if they followed up.

No dice. Reset the PRAM. Display always drops to low color depth if connected after startup. Doesn't happen in Windows. It's quite annoying to restart every time I come home.

 

[AppleSmack]

I wonder if it's a limitation/bug in your VGA adaptor. Does your monitor have other ports available like DVI or HDMI?

 

[Fishrrman]

Monitor has no other connection?

AppleSmack makes a good point in reply 8 above. It -might- just be the cable/connector/converter.

Then again, sometimes, one has to do, what one has to do.
And live with it until a better solution comes along (like a newer display)...

 

[Apples555]

Just VGA.

FWIW the adapter is a Dell MDP>VGA adapter. I guess Mac OS just doesn't play nice with this adapter. I'd rather restart every time than use Windows though.

 

[AppleSmack]

If you don't want to spring for a monitor with digital connectors, there are lots of cheap adaptors on Amazon that would be worth a try to rule out the Dell, for example:

Mini DP to VGA, Rankie Gold Plated Mini DisplayPort (Thunderbolt Port Compatible) MiniDP to VGA Male to Female Adapter (Black) - R1132 https://www.amazon.co.uk/dp/B00Z08KW8C/ref=cm_sw_r_cp_apa_4jmdzbBNGSJM2

 

[Apples555]

The issue resolved itself. Not sure why, but everything works fine now.

 

[Stefan johansson]

Do you have a normal TV set? Most of those have HDMI ports these days,try connect it to your TV.