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10.9.3 kills third monitor

The setup: 2 x 30" Cinema Displays connected via dual-port mini-DP to DVI adapters, connected to thunderbolt ports, and 50" TV connected to HDMI port, in new Mac Pro. All three monitors were working on 10.9.2, only one Cinema display and TV show up after update. Mac Pro has dual FireProD500 cards, 32 GB RAM, 12 cores.

Not sure if this is isolated to new Mac Pro's: older models with two mini-display ports and DVI to HDMI adapter may or may not still work.

Had to restore back to 10.9.2 to get all three monitors working again. Maybe they would work with mini-DP to DP cables? Not sure, have no way to test.

More users with same issue:

http://forums.creativecow.net/thread/344/30200

Mac Pro, OS X Mavericks (10.9.3)

Posted on May 16, 2014 12:26 AM

123 replies

mlsphoto

Level 1

0 points

Oct 23, 2014 6:55 AM in response to Gene Pope

Hello Gene,

Michael Schoenfeld here,

I had the same experience - bought my Mac Pro with 10.9.3 and had to find out the hard way about the "3 monitor bug" - 10.9.4 fixed things, 10.10 brought he problem back. I used my 10.9.4 Superduper clone to get back to work, so I would have to concur, that this is a REAL problem.

It's the bleeding edge of tech - you get cut - shouldn't happen, but it does sometimes. Get this - my 6 year old Mac pro, booting from a PCIe SSD from OWC with two old graphics cards and 2 old monitors FLAWLESSLY took to 10.10

It'll get sorted out I'm sure.

Michael

Map Pro 6,1

2 D700 Stock cards

64 gigs ram

1 TB SSD

Apr 25, 2015 8:11 PM in response to mlsphoto

I just purchased a new mac pro 2015 last week with everything fully loaded.

I have a new Eizo monitor plus an older Apple Cinema monitor and an older Epson projector. If I unplug the projector in and restart the Eizo and Apple monitor display correctly but if I plug in the external projector I get oversized desktops with Mirroring turned on.

I contacted Apple and they said this is a flaw in the system software and I will have to get used to it.

Any advice or direction would be greatly appreciated.

Apr 25, 2015 9:09 PM in response to SUNNY0523

I contacted Apple and they said this is a flaw in the system software and I will have to get used to it.

That person needs to be sent back for Mac Pro re-training.

System preferences > Displays ...

allows you to specify what displays are mirrored with what others:

Uncheck Mirror displays, and drag the Icons for the displays that are overlapped apart from each other and every display is part of an extended desktop, and its relative position can be set.

10.9.3 kills third monitor