OS X 10.9.2にアップデートしたMacでディスプレイの設定が消えたり、外付けディスプレイが映らなくなる不具合？

I’ve been using a Dell U2712H display for about a year with a mini-display port to display port cable.

However, after installing the 10.9.2 update, the monitor is going into sleep mode when connected to the MacBook Pro (as it doesn’t think it’s getting a signal), even though the laptop thinks it’s correctly connected. (If I turn the monitor off, the menu bar, etc. revert to the MBP screen.)

About the only related Mavericks default I’ve changed is to disable the “Displays have seperate Spaces” option within Mission Control, although I’ve tried re-enabling this and logging off/on again to no avail.

I’ve also tried resetting the NVRAM and the SMC, neither of which appear to have made any difference.

一年ほどDell U2712HをMacBook Proとつなげて使ってきたけど、10.9.2にアップデートしてからスリープモードに移行して使えない。

I’m using a 2.7 Ghz Core i5 iMac (27″) with an external 27″ Yamakasi display connected via the Apple Mini DisplayPort To Dual-Link DVI Adapter with a firmware version of 1.03.

System report is showing:

Displays:
iMac:
Display Type: LCD
Resolution: 2560 x 1440
Pixel Depth: 32-Bit Color (ARGB8888)
Main Display: Yes
Mirror: Off
Online: Yes
Built-In: Yes
DUAL-DVI:
Resolution: 1 x 1
Pixel Depth: 32-Bit Color (ARGB8888)
Mirror: Off
Online: Yes
Rotation: Supported
Adapter Type: Apple Mini DisplayPort To Dual-Link DVI Adapter
Adapter Firmware Version: 1.03

After running the 10.9.2 update, the system restarted then hung on the Apple Logo with the spinning lines in a circle for about an hour. I finally gave up and powered eveything down, unplugged all externals (display adapter, time machine drive, etc.) and restarted without a hitch. Powered down again, plugged everyting back in and powered up the external display before powering the iMac on.

System starts normally but second display does not light up and the the system report is as shown. It sees something there, it just doesn’t know what it is. I tried the mirroring checkbox and the iMac screen went dark. It wouldn’t come back and just displayed a small white dot in the center.

I restarted and zapped the PRAM (NVRAM) and it came back with mirroring off on the system preferences. One display shows up on the System preferences->Displays->Arrangement tab. Both displays show up on the System preferences->Displays->Display tab but the second display (Window shows DUAL-DVI in the title of the window) shows a dark screen and no brightness slider.

　iMacと27インチの外部ディスプレイを使ってるんだけど、 OS X 10.9.2にアップデートしてから2nd ディスプレイが映らなくなった。NVRAMクリアでシステム環境設定には表示されたけど、[Arrangement]には1つのディスプレイしか表示されない。