Jul 12, 2012, 05:09 PM
Dual Screens flickering - Mountain Lion - Windows 7 - Parallels 7
When I try to use two displays with windows 7 i'm getting this weird flickering on the external monitor. Basically when I try to click on something on the external monitor I will briefly see the main monitor displayed just for an instance, but repeatedly. It flickers.
I'm using a macbook pro (last year's) with mountain lion and windows 7.
I was not getting this issue before i upgraded to both Mountain Lion and Parallels 7, but I upgraded both on the same day so I can't be sure which one is causing issued.
Any ideas or help would be appreciated.
Jul 13, 2012, 11:44 AM
I upgraded to the first mountain lion beta and didn't have any problems. After the second developer preview I began to experience the same thing. There are threads that suggest ideas (from old parallels having this problem) and none of them seemed to fix it.
While I do development, I have to have a working windows virtual machine for day to day job. So I ended up downgrading back to OS X Lion and setting up again; which cleared the problem. I just updated to the gold master as I saw a release of parrallels claiming support for mountain lion hoping it was fixed. It is not fixed.
So all of that aside, its a touch more history to when it started, and seconding the fact it isn't fixed.
Jul 17, 2012, 02:55 PM
Thanks. I'm just using one screen for now (I use parallels at work with two monitors), but it's frustrating. Hopefully either parallels or OSX comes out with a fix.
Jul 19, 2012, 09:30 PM
I have this exact same issue. Hope there's a fix soon.
Jul 25, 2012, 11:50 AM
I am experiencing the same issue. Any possibility for a fix?
Jul 25, 2012, 12:18 PM
The problem seems to go away when I turn off 3D acceleration in the config for the VM.
Hopefully Parallels will fix this soon, so I can turn it back on...
Jul 25, 2012, 04:08 PM
That worked for me
Turning off 3D in the video configuration worked like a champ. Thanks!
Jul 25, 2012, 05:15 PM
Same problem for me... Turning 3D acceleration solved the issue, but no transparency anymore...
Jul 25, 2012, 05:45 PM
Same problem on 3 monitor setup
Left monitor (main) is blank, center and right monitor work, but right monitor is flickering. Switching of 3D acceleration seems to stop this flickering issue, but the left monitor is still blank.
Jul 26, 2012, 05:58 AM
I have the same issue since upgrading to Mountain Lion when I have Parallels full screen on my 2nd monitor. Disabling 3d made it stop and it also doesn't do it when I have iShowU (screen capture software) open with the recording area set to the OS X screen, but not recording.
Jul 26, 2012, 10:40 AM
I'm getting exactly the same issue since upgrading to Mountain Lion and latest Parallels v7 update...
Jul 26, 2012, 10:50 AM
Might not be a "flicker"
I'm on the phone with Apple Support as I type this...
This may not be a "flicker" at all. It APPEARS to me that the problem is the OS REFOCUSING the applications when it should not be. Depending on how fast the screen / application redraw the app the result appears to be a flicker.
For example, leaving Mail open on one of the external displays, while you are working in a separate app, causes the tool bar to constantly enable and disable the buttons. Some other apps (Safar, Chrome, etc.) cause the entire app to redraw itself. Leaving an animated GIF or movie running in the browser causes that PORTION of the UI to "flicker."
Man, I hope that made sense.
Jul 26, 2012, 11:06 AM
Just upgraded to Mountain Lion and now my quad screen setup is rendered redundant. When in my Windows 7 vm Windows can only detect a single screen. Tried disabling 3D etc but same problem.
The team at Parallels need to spend more time testing with multiple screen setups. I would think that most users who run Parallels are power users who have multiple screens.
I guessed that upgrading to Mountain Lion would cause problems with my screen setup and I guessed right. It would be nice if just for once I could upgrade my os without having to wait for a parallels update.
Jul 26, 2012, 11:20 AM
Same issue here
I installed Mountain Lion yesterday and now my Windows7 VM started flickering terribly. This was not an issue before upgrading to Mountain Lion. I use two monitors all the time.
Hopefully this gets addressed soon as it is extremely annoying.
Last edited by santiagoIT; Jul 26, 2012 at 01:58 PM.
Jul 26, 2012, 12:59 PM
I have the same problem. In OSX there is no flickering, it's just Desktop parallels.
Jul 26, 2012, 02:21 PM
Same issue here, connected my macbook pro and cinema display. Run windows 7 on Mountain Lion, the screen on macbook pro flickers. Doesn't matter if you use OSX full screen mode or parallels, also doesn't matter if you use all monitors in fullscreen mode or not.
Jul 27, 2012, 04:45 AM
Same here. Disabling 3D hardware acceleration does work, but it would be nice if Parallels could do something about it. I can't imagine that they can't reproduce this problem as I am experiencing this problem on 2 different machines (iMac 27" Mid 2010 and MBP end 2011).
So please Parallels could you please FIX IT?!
Jul 27, 2012, 07:30 AM
Same here... The only Way is to disabling 3D - but this is not a solution...
Has Parallels not tested the actually Parallels Build on a Golden Master Beta from Mountain Lion?
Jul 27, 2012, 09:20 AM
I disabled the 3D in the video config but i steal have flickering on other screen used.
Do i miss something ? it's driving me crazy
Last edited by PeymanN; Jul 27, 2012 at 09:23 AM.
Jul 27, 2012, 11:32 AM
Videos Sent to AppleCare
Here are a few videos that I sent to AppleCare regarding the flicker problem...
To me, it appears that the window manager in Mountain Lion is not disposing of the last state of the application or its controls. For example, since Parallels has focus and Safari just lost focus, it appears that Safari is bouncing beteen the state of having focus and NOT having focus. Similarly, in the video with Pulsar in it, the label controls that HAD a previous phrase within them are constantly jumping between the new text and previous.
Hopefully Apple will escalate this soon.
Last edited by Fred Lackey; Jul 27, 2012 at 11:35 AM.
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