Research firm Gartner last week reiterated an earlier forecast that Microsoft won't meet the November corporate deadline.

In an online brief posted on the Gartner Web site, research vice president Steve Kleynhans applauded Vista's most recent build as not only stable enough to use day-to-day, but also as significantly better behaved than the original Beta 2, which was released to the public in May.

"However, there are still a lot of holes under the surface," said Kleynhans. He named graphics drivers as among the areas yet to be addressed.

"I've begun noticing a large number of small glitches and failures which can't be reproduced, and while performance is much better, it is also unpredictable. It's not unusual to find my system suddenly lock up for minute or longer," he added.

"Based on more than 15 years of experience with Microsoft beta programs, I'd say they are getting close, but they are into the hardest part of the testing: finding the corner cases and quirky bugs, a phase that can take from three to six months.

"While Microsoft is certainly making progress, I don't expect to see a finished product in November," Kleynhans concluded.