Update at 8:35 a.m. PT on Wednesday: Since ZDNet UK published this article, a patch for the flaw has been posted to VMware's Web site.
VMware virtual machines on all hosts with the company's latest hypervisor, ESX 3.5 Update 2, in enterprise configurations have found that it will not power on after being turned off.
The hypervisor refuses to start when the date is August 12, with customers around the world discovering the problem as midnight was passed in their time zones. A flaw in the VMware licensing code is responsible, according to Martin Niemar, group manager of virtual-infrastructure product marketing at VMware.
"We had an issue with 3.5 Update 2. It's actually a licensing problem," Niemar said. "Currently, what we know is that licensing prevents new virtual machines from powering up after shutdowns, and it prevents virtual motioning--moving a virtual machine from one host to another."
Niemar said VMware does not have a patch but that working on one is a "top priority."
"Customers should not stop virtual machines. Keep virtual machines going until we release a patch," Niemar had said. "You can also move the clock backwards on the server."
Some organizations cannot turn server clocks back for legal or technical reasons. Niemar said that, if customers have to turn machines off, and cannot turn clocks back, there is currently no fix. (Editors' note: A patch is now available on VMware's site.)
Niemar could not commit to a time line for a patch, nor could he comment on forum claims that the fix will first be available to customers as a complete reinstallation from ISO or TAR images, with a patch for installed code coming later.
"We understand the bug," he said.
VMware first learned of the issue when Asia-Pacific customers started to come online on August 12. Technical issues have been discussed on the VMware communities blog.
"VMware engineering has isolated the root cause of this issue and will reissue the various upgrade media, including the ESX 3.5 Update 2 ISO, ESXi 3.5 Update 2 ISO, ESX 3.5 Update 2 upgrade TAR and ZIP files by noon, PST, on 13 August," one poster wrote. "These will be available from the page: http://www.vmware.com/download/vi. Until then, VMware advises against upgrading to ESX/ESXi 3.5 Update 2. The Update patch bundles will be released separately, later in the week."
At the time of writing, ZDNet UK was unable to confirm this comment.