Mavericks 10.9.3 Update Has Disabled Two of My Quad Monitors

I have a Mac Pro 2014 with four 24 inch monitors attached. Two of them are DVI monitors, two of them are HDMI. 3 of them are attached to thunderbolt connections with Active Display Port conversion kits, one is plugged directly into the HDMI port. They were all working swimmingly until today's Mavericks 10.9.3 update, which will now not allow me to have more than 2 of them connected simultaneously. This is incredibly frustrating... I'm guessing it has something to do with the 4k monitor fix contained in the update. Any ideas for a fix? Unfortunately, I didn't do a Time Machine backup prior to the update.

Posted on May 15, 2014 12:52 PM

18 replies

fadem18

Level 1

0 points

Jun 12, 2014 8:18 PM in response to djbene

June 11, 2014 - Update: Having the same problem. Upgrading to Mavericks 10.9.3 made it impossible to display with two monitors (one HDMI --> HDMI and the other HDMI --> thunderbolt). I spoke with a second tier Apple support technician who was aware of the issue thanks to the posts above, promised engineering was working on a fix, but had no idea of the release date. They told me to role back 10.9.2 through Time Machine. Once I did, the two monitors were instantly displayed.

Jun 16, 2014 1:05 AM in response to fadem18

Apparently 10.9.4 will solve our issue.

Need to stick to 10.9.2 until then...

Jul 1, 2014 2:09 AM in response to Lorenzo S

Confirmed: 10.9.4 does solve the issue.

Source: I installed it: 4 monitors via DVI (2 active 2 passive) @1920x1200 working on 10.9.4

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Mavericks 10.9.3 Update Has Disabled Two of My Quad Monitors