Windows Update bug brings computers to crawl with scan

Windows administrators are grappling with a bug that surfaced last week in the Microsoft Update scan engine that impedes performance of a client while undergoing a routine scan.

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According to IT experts at MyITForum.com, a site devoted to covering Windows manageability, the problem can cause Microsoft Update and Windows Server Update Services (WSUS) around five minutes per scan on a client.

"During the scan the processor utilization spikes and is maintained by the scan," according to Microsoft's analysis of the problem posted on the site.

"When a computer is scanned, there is a lot of hard disk utilization anyway, but it takes a lot of CPU cycles to do the scan," said one expert. "So both hard drive and CPU are being impacted."

IT administrators in companies that don't have all the latest computers with plenty of RAM will likely be the hardest hit.

Initially, administrators thought the bug was connected to the Inventory Tool (ITMU) for Microsoft Updates in Systems Management Server, Microsoft's desktop management software. ITMU determines the management compliance of managed systems. Anti-virus scanning was also suspected.

But Microsoft has determined that it was not just an SMS issues but a bug in how Microsoft Update scan works, according to Robert Stack, a London-based SMS administrator in a post to MYITForum.com.

Microsoft has identified reasons for the slowdown. They are:

• Older hardware -- a slow disk and CPU will increase scan time and CPU usage
• Growing catalog
• Software competing for CPU cycles, such as anti-virus software
• Busy computer at logon. Adding a scan on top of other logon items will impact the CPU and increase the scan time

Microsoft has said it is looking into potential solutions to the problem. The company is suggesting as one workaround to schedule the scan and patch installation during non-business hours. This option won't help laptop users who would be affected as soon as they log in.