After upgrading from a 2011 MacBook Air to a (refurbished) mid-2013 MacBook Air, I'm getting odd behavior with my external Dell 2240M monitor.

Whenever my laptop wakes up, if the monitor is already on (usually asleep), there are this static-like white dots dancing all over the screen. If I cycle the monitor power with the laptop on, they go away.

What causes this? Does the newer MacBook Air have some incompatibility older monitors?


I'd start by suspecting the thunderbolt->DVI adapter you're using (you are using DVI, right?).

Do the dots go away if you just unplug and replug the adapter, or do you actually have to power cycle the unit?

  • Thanks Colin. It's DVI from the monitor to a DVI-to-HDMI adaptor to an HDMI-to-Mini-DisplayPort adaptor into the MacBook Air. I know that's a bit convoluted, but it worked fine for the older MacBook Air. The dots do NOT go away if I unplug and replug, only if I power cycle the monitor. – Ghopper21 Aug 14 '14 at 22:58
  • I have the same issue with thunderbolt to HDMI on mid 2014 macbook pro. Unplug and replug the adapter does fix the issue. Any suggestions to resolving it without unplug/replug every time? Do I need a different (better?) thunderbolt to DVI/HDMI cable? – RjOllos Feb 1 '17 at 0:16
  • Using DVI to DVI cable rather than Thunderbolt to HDMI seems to fix the issue for me. – RjOllos Feb 1 '17 at 2:40

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