Microsoft says recent security updates made to computers running Windows 7, Vista and XP operating systems are not to blame for the "black screen of death" some users are having on their machines, which results in the computer shutting off.
However, it was still unclear Tuesday what the source of the problem is. It is the first of any scope to affect users of Windows 7, the software maker's newest operating system which became available in late October. Microsoft said if there is a problem, it may be tied to malicious software, or malware.
"Microsoft has investigated reports that its November security updates made changes to permissions in the registry that are resulting in system issues for some customers," said Christopher Budd, security response communications lead member for the company. (Msnbc.com is a joint venture of Microsoft and NBC Universal.)
The company, Budd said, "has found those reports to be inaccurate and our comprehensive investigation has shown that none of the recently released updates are related to the behavior described in the reports."
Windows users are familiar with the "blue screen of death," when their computers essentially shutdown because of an operating system problem. The new "black screen of death" appears to occur when the computer is first turned on, then shuts down.
"We’ve conducted a comprehensive review of the November Security Updates, the Windows Malicious Software Removal Tool and the non-security updates we released through Windows Update in November," the company says on its blog.
"That investigation has shown that none of these updates make any changes to the permissions in the registry. Thus, we don’t believe the updates are related to the 'black screen' behavior described in these reports."
British security firm Prevx wrote about the problem on its Web site, offering a procedure to fix the problem by those who have experienced it, saying it might be caused by a security update issued by Microsoft in November.
"I must stress that this tool will not fix all black screen issues," wrote Dave Kennerley of Prevx Support on the company's blog. "There can be many causes. But if your black screen woes began in the last two 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."
But Microsoft said it is not seeing the security updates as "an issue," and that the British security firm's "claims do not match any known issues that have been documented in the security bulletins or (the company's) Knowledge Base articles."
On its blog, the company said it has "checked with our worldwide Customer Service and Support organization, and they’ve told us they’re not seeing 'black screen' behavior as a broad customer issue. Because these reports were not brought to us directly, it’s impossible to know conclusively what might be causing a 'black screen' in those limited instances where customers have seen it. However, we do know that 'black screen' behavior is associated with some malware families such as Daonol."
Said Budd of Microsoft: "As always, we encourage customers to review the security bulletin and related Knowledge Base articles and test and deploy security updates.
"If customers do encounter an issue with security updates, we encourage them to contact our Customer Service and Support group for no-charge assistance" at http://support.microsoft.com/security."
Prevx said on its blog late Tuesday, "We've been working with Microsoft to get to the bottom of the specific black screen issues in our earlier blog," and added: "We apologize to Microsoft for any inconvenience our blog may have caused. This has been a challenging issue to identify. Users who have the black screen issue referred to can still safely use our free fix tool to restore their desktop icons and task bar."
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