Yosemite Update: Secondary Monitor Display With Limited Resolution Choices

Yosemite Update: Secondary Monitor Display With Limited Resolution Choices

 

THE SYSTEM
2015 MacBook Air
2012 MacBook Pro 15″
NewerTech Mini DisplayPort to VGA Adapter
Yosemite
ProPresenter 5
Optoma TW610 ST projector (connected via VGA)

THE PROBLEM
With the Yosemite update, the secondary monitor display options are limited to only 2 resolutions:
1280×1024 and 800×600.
There are no other options available under the “Scaled” option.

Yosemite secondary display resolutions
After blaming the Thunderbolt to VGA adapter, the cable, the projector, the user (me),
the host software (in this case ProPresenter 5), hardware (a 2015 MacBook Air), it came down to an OS problem with Yosemite.
It seems Yosemite is no longer able to auto sense what’s connected through the Thunderbolt port when it comes to VGA and it does not allow you to choose from a list of possibilities.

As a side note, I did try a Thunderbolt to HDMI adaptor that worked correctly
(i.e. showing me all available resolutions).
However, there wasn’t a 50′ HDMI cable available.

How do I know it’s not a hardware (2015 MacBook Air) issue?
Because an older MacBook Pro (Mid 2012) with a fresh install of Yosemite had the same issue
and the only thing in common was Yosemite.

Needless to say, this has driven me nuts for 2 weeks.

THE SOLUTION
After more research, the solution is to hold down the “option/alt key
when selectingScaled” in the monitor preference.

BAM!

Now all available resolutions including the one I need (1280×768) are shown.
Yosemite secondary display resolutions - all available

there are different refresh rates selected between the above images; refresh rates had nothing to do with what resolutions were available;
just wanted to make a note

So, thanks Yosemite for all the stress and aggravation for the last 2 weeks.

This seems to have been an issue with Mavericks as well.

 

Why did it take 2 weeks to figure this out? because I only have access to the system for a few hours on Sunday mornings
and have limited time to research during the week due to the fact that I’m simply a volunteer tech
and have a day job and evening responsibilities. 

 

YOSEMITE:
http://www.iclarified.com/49262/how-to-display-more-screen-resolution-options-in-mac-os-x
https://support.apple.com/kb/PH19043?locale=en_US

MAVERICKS:
https://discussions.apple.com/thread/5469819

 

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