OS X Lion black-screen bug likely from hardware malfunction

When OS X Lion was released, a number of users who installed the operating system on a MacBook Pro began experiencing a black-screen bug when waking the computer from sleep or when performing some graphics manipulation tasks. When this issue initially appeared, it was suspected the problem was in the handling of the systems' graphics processors by Lion, but more recent reports suggest the problem may be a hardware fault in the affected systems.

Many of those who have experienced this problem have reverted back to OS X 10.6 Snow Leopard and have seen the problem go away, suggesting the issue was a software-based problem; however, this does not disprove hardware malfunctions. While the black-screen problem has been less prevalent in Snow Leopard, it still has occurred for some users, suggesting the different OS merely triggers the problem less often rather than fixing the issue altogether. In addition, some Boot Camp users have found the problem occurs when running Windows as well, so even with vastly different hardware management routines the problem persists.

While some iMac and Mac Mini users have reported this problem, the issue seems to primarily affect MacBook Pro systems, and specifically the 15-inch and 17-inch Mid 2010 models which used the Nvidia GeForce 330M GPU. It appears some problem with handling the GeForce 330M results in random occurrences of the black screen. Even after over a month of testing and investigating the problem, users have not been able to replicate the problem on demand. As a result, many of the computers sent in for repair have been returned without the technicians being able to replicate the issue, only to have the problem show up again.

For a number of systems, Apple support has replaced the logic board which contains most of the system's components (CPU, GPU, controllers, and so on), and for these systems the problems have disappeared. In a few cases the problems were still present, but were fixed by having technicians replace the motherboard yet again. This indicates the problem is rooted in the hardware of the systems.

The issue at hand may be a temperamental hardware condition in these systems that is exacerbated in Lion because of differences in how it handles graphics. The specific cause of the problem is anyone's guess at this point, but there are some indications that it may be from sudden heat spikes, which can happen in a matter of seconds if a GPU or other high-heat component is not properly cooled. The problem happens more when systems are performing heavy graphics manipulations, and some users have found that the problem has gone away after they after installed the utility SmcFanControl to keep the system fans blowing at their maximum levels.

While having the motherboard on your system replaced seems to be a more permanent fix that has worked for some people, for others this may not be required. Here are some of the workarounds that seem to have been successful so far:

1. Install GfxCardStatus
   The problem has something to do with the discrete graphics card on the system, whether it is with the power management or heat management of the unit. Regardless of the specifics, you can install GfxCardStatus and use it to force the system to run on the onboard GPU, which should fix the problem. Merely installing GfxCardStatus will not do this, so be sure to configure the program to only allow the internal GPU, and the black screens should stop.

2. Run SmcFanControl
   The utility SmcFanControl can be used to govern the fan behavior on Mac systems, and for some people forcing the fans to run at high speeds has reduced this problem, if not eliminated it. Try installing the program and adjusting the fan speeds to see if that helps. In addition, you can try monitoring your graphics processor temperatures using a tool like Temperature Monitor, to see if any spikes in the graphics card temperature are occurring on your system.

3. Delete the Power Management preferences
   This issue may also be rooted in how the system is handling power settings for various power sources (battery or wall power), and some people have claimed success in preventing this issue by removing the power management preferences so the system will rebuild them. The preferences are located in the /Macintosh HD/Library/Preferences/SystemConfiguration/ folder and are called "com.apple.PowerManagement.plist."

   Remove this file and restart the system, and that may help the situation, especially if the problem only happens after waking from sleep. The preferences contain GPU switching instructions for various power modes, which may be what is triggering the problem for some systems.

4. Replace the motherboard
   The above workarounds and fixes will likely not fix the problem fully, but just provide a more tolerable working environment for the issue and thereby allow the system to function without showing the problem, or at least reduce the prevalence of the problem. Therefore, until Apple addresses this problem specifically with some sort of firmware update, then the only true fix for this issue at the moment is to have your system's motherboard replaced. Most people who have had this done have found the problem has disappeared completely. Apple may be reluctant to do this, especially if its technicians cannot find any problems when testing the machine, so be sure to insist that this be done when you talk to the Apple technicians, especially if you have tried all other routes and workarounds.

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