|
By Cara Garretson
Prevx on Friday posted a fix for a recently discovered problem that is causing Windows-based PCs to freeze up. The issue, according to Prevx, stems from Microsoft's latest round of security patches.
Prevx, a U.K. maker of Web security products, has released for free a fix designed to recover some PCs running Windows that freeze up inexplicably and display only a black screen. The problem, according to David Kennerley, who authored a blog post describing the issue, is happening when some PC users boot up their systems running Windows 7, Windows Vista, Windows XP, Windows NT, and Windows 2000. The start-up process appears normal until the user logs in; at that point there is no desktop, task bar, system tray or side bar displayed, only a totally black screen with a `My Computer Explorer' window.
The cause of this recent round of black screens appears to stem from a change Microsoft has made in the Windows operating systems via its November crop of monthly security patches. "This change has the effect of invalidating several key registry entries if they are updated without consideration of the new ACL (access control list) rules being applied," says Kennerley, adding that the black screen issue could affect millions of Windows users. The access control list is responsible for describing the individual object permissions for each logged-on user, among other things.
On Nov. 10, Microsoft released six security bulletins designed to address 15 vulnerabilities. Four of those bulletins affect Windows and Windows server.
Microsoft said Monday that it is investigating reports that its security updates are resulting in “some issues” for customers, according to a Microsoft spokesperson. It plans to provide guidance on how to prevent or address the problem once the investigation is complete.
Prevx says it has discovered at least ten different scenarios that will trigger the black screen condition. The company's Black Screen Fix will resolve the most common cause, but won't work in every instance. Instructions for running the fix are available on the company's blog post that describes the problem.
"I must stress that this tool will not fix all black screen issues. There can be many causes," says Kennerley. "But if your black screen woes began in the last 2 weeks after a Windows update or after running any security program (including Prevx) to remove malware during this time then this fix will have a high probability of working."
Thousands of users who have encountered the black screen have resorted to reloading Windows as a "last-ditch effort" to fix the problem, says Kennerley, who advises to avoid taking that step at all costs.
In the past few weeks, a number of posts to Microsoft-hosted forums, such as TechNet and Microsoft Answers, describe the black-screen problem. Microsoft moderators on the forums have described some potential work-arounds, but have not acknowledged that the problem may stem from ACL conflicts caused by the November security patches.
Only registered users can write comments.
Please login or register. |
