Security Update 2015-002 Broken Mac-Mini Late 2012 Dual Monitors?

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Security Update 2015-002 Broken Mac-Mini Late 2012 Dual Monitors?

I installed the latest security update on the 10th. Since then, my second monitor (via Thunderbolt) has been broken. Upon startup, both monitors work. However, on login, the thunderbolt monitor goes black.

The OS thinks it's still there, but there's no video signal on the monitor. Naturally, it goes into power-save mode after a few seconds. Even when it's woken up, there's still no signal. Very annoying as half of my desktop is trapped on a monitor that isn't working.

I tried swapping monitors. Whichever one is attached to thunderbolt is the one that doesn't work.

Mac mini, OS X Yosemite (10.10.2)

Posted on Mar 12, 2015 4:14 AM

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Answer 1

lllaass

Level 10

210,411 points

Mar 12, 2015 4:25 AM in response to RandomJ

Try resetting the SMC and NVRAM

Intel-based Macs: Resetting the System Management Controller (SMC)

About NVRAM and PRAM

Do both work in Safe Mode

OS X: What is Safe Boot, Safe Mode?

reinstallthe security update

Security Update 2015-002 Yosemite (Early 2015 Mac)

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Answer 2

RandomJ Author

Level 1

10 points

Mar 18, 2015 3:27 AM in response to lllaass

I tried the above - no dice. I even bought a thunderbolt hub and attached the monitor to that via HDMI. Same problem.

I created a fresh installation of Yosemite on another drive, booted off it. Then did the OS upgrade via the App Store. The 2nd monitor stopped working soon thereafter. This is on a fresh install of Yosemite, with nothing else except the latest OS updates.

I'll try installing Mavericks and see if that has the same problem. I guess if it does, then it's a hardware problem.

BTW, with the mini's system memory mapped graphics, is it possible I have a RAM problem?

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