Q: Mac Mini (2012) HDMI losing sync (blank screen/snow)

Removing monitor configuration files worked for me. Now I have sound to my TV and monitor after putting my Mac Mini (Late 2012) to sleep.

Just deleted these files:

/Library/Preferences/com.apple.windowserver.plist

and

~/Library/Preferences/ByHost/com.apple.windowserver.(something).plist

Found from:

http://superuser.com/questions/165108/misconfigured-external-monitor-on-mac-os-x -snow-leopard-10-6-3

Well, I took it to Apple and they fixed it overnight: replaced the RAM. Seems fine now, and I hope it stays fixed — that's the trouble with randomly occurring faults, one never knows whether they will resurface at some unpredictable moment

So much for different monitor cables, ferrite rings adapters, etc.!

Thanks, everybody, for help and advice, and I hope you will all in the end solve your similar (or dissimilar) problems, too.

Good news, the RAM was one of my initial suggestions, but I did not expect faulty modules, just the contacts of them.  As for me, the screen problems were eliminated, using an original Apple thunderbolt->DVI cable. 

Well, I am really glad you are out of trouble, as well. Thanks for your advice earlier on, too.

Glad to hear that your problem is solved Michael. I have added my old VGA but very serviceable display as a second display, using a thunderbolt to VGA adapter cable. I was hesitant because I didn't want to start a problem, but everything is great-- the old display has never looked better and both monitors are rock steady.

I'm glad your stuff is working well, too, Bobmepp. I have no need of two monitors and, in fact, barely have room for one on my desk, but it's good to know that two will work OK in case I ever need them.

I have the same problem with my late 2012 i7 mini, I usualy put the monitor to sleep after a peroid of time, when the monitor wakes up, I get the snow sometimes. It is very annoying, this is how I got around the issue.

In the Display and Screen Saver perference under Screen Saver, set one of the four Hot Corners to Put Display to Sleep. When the snow comes up, just drag the mouse to the coner for a short time to put it to sleep then wake it up, the snow goes away.

This is a work around. I am disappointed that Apple would release an imperfect product. I use Apple exclusively (I have an iMac, MBA and the Mac mini) because I like Apple's products for the most part. And I don't mind paying more for a good Apple computer rather than save a few bucks on a garbage Windows PC. But I expect less then perfection from Apple.

Hopefully Apple will provide a fix for this.

I recently discovered, that if i turn-off then turn-on the monitor - quicky, I have the "snow" screen.

I think the video output of the mac mini is "autosense" (to detect if the monitor is on/off) and loses the signal in this case or something like that.

I have mac mini i7 and dell S2240L monitor , snow and blank screen was my problem too . I attached large ferrite cores which were supplied with my panasonic plasma tv to the monitor hdmi cable as close as possible to the connectors. Problem solved. We have a lot of equipment on one table , I think electromagnetic interference between the devices could cause snow .

hello,

I have same problems with snow/losing signal but I have mac mini middle 2011 ? Powered on mini, picture is OK and then before login window showed snow - sometimes is picture back itself after few seconds, sometimes I disconnect/connect HDMI, power off/on monitor unitil I see picture.

I replaced HDMI cable and it is the same.

I cannot try original DP-DVI cable, because I have only HDMI input on monitor and I don't have DVI-HDMI cable.

Just to not let theme/thread to die. New mac mini (late 2012), Mavericks, the same problem with blank/flickering screen.
Apple shame on you. I am using apple hdmi to dvi adapter.

Monitor that have been tested:
new Dell u2412
new Dell P2414

I think that we need to put some effort using social networks to address this problem to Apple. So let's spend some of their marketing money the right way.

You are right. We need to get Apple to admit their faulty product just like GM recalls their cars. I have stopped using any other PCs because I liked Apple products' quality. But the i7 Mac mini has proven to me Apple is no better then any other cheap PC makers such as HP, Dell.... Especially after spoken to serval Apple "Geniuses" , Apple knows about the issue but do nothing.

<Edited by Host>

Just wanted to add my name to the list... Mac Mini (Late 2012) w/Crucial Memory Upgrade to 16GB, dual display ASUS VS278p-q 1080p 27" LCD displays - one connected with thunderbolt to mini display port the other connected HDMI to HDMI (neither using any type of adapter). I have replaced cables and swapped monitors (I have three identical 27" ASUS LCD monitors in my office) ANY one of the 27" monitors connected to HDMI output will periodically go black for a few seconds then return (most of the time it returns without issue other times it is garbled and occasionally only a power cord unplug will resolve the issue). It is not a isolated monitor or cabling issue as all have been replaced in multiples. The problem is ALWAYS on the HDMI output ONLY.

Other notes (of importance?):

• This configuration ran without incident for over a year with Samsung 23" 1080p LCD's (HDMI-HDMI without adapter, thunderbolt to HDMI with adapter)
• The problems began AFTER I upgraded to 27 inch monitors. I'm not switching back... the mini will go before I go back to 23" LCD's.
• The problem "seemed" to be worse when display sleep was engaged... I tried disabling the display sleep for a while and now neither the sleep or screensaver will (re)enable.

It's shameful that so many people are reporting this problem and Apple is not offering any visible assistance in this thread or with this issue.

Its more than a  year that I used the thunderbolt to DVI  (DVI on my monitor) without any issues, because the (included with the mac mini) hdmi to DVI

caused all that sh*t.  Well, after I upgraded (18-Oct) to Yosemite I use again the mac mini's hdmi to DVI without any issues so far.  

I finally bit the bullet and upgraded to Yosemite.

The HDMI blanking problem was not resolved by the upgrade, but my monitor hibernation and screensaver have begun working again post upgrade.