Some users of Citrix thin client technology suffered frozen systems or reduced performance after encountering problems with a routine Microsoft software update for Windows 2000.
Users who contacted Computer Weekly said they felt that both Microsoft and Citrix should have done more to warn them of the problems that would be caused by the application of Update Rollup 1 for Windows 2000 SP4 - a 31Mbyte systems patch.
Kidderminster-based Brintons Carpets, which runs Windows 2000 desktops on Citrix Presentation Server 3.0, experienced 12 hours of downtime after installing the update.
Bryan Cowley, the company's group head of IT, said he applied Update Rollup 1 to address problems with terminal servers hanging for 10 to 15 seconds.
But after the company ran the update, the winlogon.exe application, which is key to the update, hogged the processor, causing the system to freeze.
Cowley said, "The net effect of this procedure left us without mainstream computer systems for 12 hours of prime time while we searched for the source of the problem and then fixed it."
Uninstalling the patch and rebooting all the Citrix servers fixed the problem for Brintons Carpets, but this did not work for all users.
Other companies reported similar experiences on the Citrix User Forum website, with some IT managers complaining of problems with Windows 2000 workstations, Microsoft Outlook 2003, Outlook XP and Internet Explorer.
"We followed [Citrix and Microsoft's] recommendation to install the 'critical' update and suffered for it," said Cowley.
He criticised Microsoft for releasing "essential" software upgrades that he said could not be trusted to work in a mainstream environment. Cowley also criticised Citrix for failing to adequately alert users to potential problems.
Citrix said it had posted an article on its Knowledgebase website acknowledging some of the problems caused by the update, but Simon Frost, product architect at Citrix, said, "We had early access to the Update Rollup Pack and tested it. Issues were found and reported to Microsoft, and this was reflected in the final release.
"Unfortunately, the testing missed the particular scenario required to trigger the problem outlined. Once the problem became known, Citrix published a workaround and then worked with Microsoft to get a fix available for Update Rollup 1."
Microsoft also acknowledged the problems caused by the initial patch and in response released version two of Update Rollup 1 for Windows 2000 SP4.
Despite the release of the fix, Rob Bold, technical consultant at Brintons Carpets, remained frustrated. "Citrix and Microsoft often boast about the partnerships they are forging and how closely they are working together, so how come mistakes like this still happen?" he asked.