Following the recent furore over a Microsoft application that regularly checked in with the company, Apple users have discovered, to their concern, that Mac OS X is doing much the same thing.

Windows users were irate because a component of Windows Genuine Advantage - which Microsoft classified as an urgent update, ensuring it was downloaded automatically by large numbers of Windows systems - dialled back to Microsoft once a day.

The component, which displays warnings if it thinks a version of Windows is not properly licensed, was not removable - at least not until Microsoft bowed to user criticism.

Earlier this week, Mac developer Daniel Jakult noticed that last week's Mac OS X 10.4.7 update caused the operating system to check back to, once every few hours.

The feature was alluded to in Apple's release notes as a security feature allowing users to "verify whether or not a Dashboard widget you downloaded is the same version as a widget featured on before installing it," but no details were given.

"The problem is this feature popped up without my permission, and there’s no obvious way for me to turn it off. This is how companies, even fairly trustable ones (IMHO) like Apple, make users paranoid and suspicious of them," Jakult wrote on his blog.

"I can’t see that anything at all is being sent back to Apple, but that’s sort of not the point. The mere act of 'checking in' lets Apple know that I’m here and I’m running 10.4.7."

Jakult detected the unauthorised traffic via an application called Little Snitch, which can also be used to block the check-ins.

One of Jakult's readers said the feature is a particular annoyance to those managing large numbers of Macs. "I reguarly have to answer to my network administrators for unidentified or mystery traffic coming from the Macs that I maintain," the reader commented.

"In my larger managed computer environment, this stealth update by Apple has put the final nail in the coffin for Dashboard. It will be disabled in our environment in the fall."

Most readers agreed the check-in seemed relatively innocuous, but set an uncomfortable precedent. "How long before Apple builds a keylogger into Spotlight, just to see how people are using the search capabilities?" one wrote. "It is a slippery slope."

An Apple representative said the Dashboard Advisory feature is designed for security, and doesn't transmit personal information to Apple.