"Microsoft is investigating reports that its latest release of security updates is resulting in system issues for some customers," said a company spokesman.
"Once we complete our investigation, we will provide detailed guidance on how to prevent or address these issues."
The reports Microsoft alluded to stemmed from security vendor Prevx, which claimed that the Windows security updates issued on November 10 changed Access Control List (ACL) entries in the registry, preventing some installed software from running properly.
The result, said Prevx, is a black screen , sometimes dubbed 'Black Screen of Death' similar to the 'Blue Screen of Death' that Windows puts up after a major system crash.
Prevx added that security software seemed to be especially affected.
Although the Microsoft spokesman said the company would provide additional information once its support and security teams complete their investigations, it was unclear exactly how extensive the problem was, or how many users were affected.
Searches of Microsoft's support forums today, for example, turned up only one 'black screen' thread with posts after the November 10 security updates had been released. Four different users on that Windows 7-specific thread said that they faced a blank screen.
On November 19, a moderator of the support forum suggested a workaround that involved starting another Windows Explorer (explorer.exe) process.
Prevx essentially gave the same advice a week later when it told users with blank screens how to download a free tool it said would fix the problem.
Microsoft's November collection of patches addressed 15 vulnerabilities in six security updates.
Only one of the half-dozen updates included a known issue. According to the detailed support document for MS09-065, one of the month's three critical updates, customers running Windows XP and using an ATI Radeon HD 2400-series video card "may find that the computer does not start correctly."
Microsoft's next security update release is slated for December 8.