Citing installation issues and inadequate testing, Microsoft has withdrawn an Exchange Server 2013 security update that it issued earlier this week as part of its "Patch Tuesday" release cycle.
This is the second month in a row that Microsoft has withdrawn a patch because it could cause problems for the system it was designed to repair. In July, the company recalled four buggy patches.
When installed, the MS13-061 security update for Exchange can impede access to the content indexes for mailbox databases and may also rename the Exchange Search Host Controller service.
Microsoft advised against installing the patch. For those who have already installed it, the company offered instructions to fix the problem, which involves editing registry keys.
Microsoft had failed to test the patch correctly, it admitted.
"Unfortunately, this security update did not get deployed into our dogfood environment prior to release," Microsoft said in an alert.
The bug doesn't affect Exchange 2007 or Exchange 2010 because they have a different architecture.
Microsoft also withdrew a patch last December.
Despite the series of missteps, "I don't see this as indicative of a larger quality control problem at Microsoft, but rather of a consequence of the high degree of variations that one encounters in the enterprise software market," Wolfgang Kandek, CTO of security and compliance software provider Qualys, said via email.
He said it's virtually impossible for enterprise software vendors to quickly test an update across all the possible hardware and software combinations.
To mitigate potential damage from faulty patches, Kandek suggested customers test the update in a controlled environment before rolling it out across the entire organization.
He also advised organizations to stick to popular hardware and software configurations as much as possible, to increase the chances that a patch will have been tested against their own setup.
Migrating to the cloud is also an option, Kandek said.
"In Microsoft's case it is much easier to make sure Office 365 works perfectly or even hosted SharePoint, than assuring that their software will operate as designed in all different customer environments," he wrote.