A week after launching with great fanfare its Apps Sync for Microsoft Outlook, Google has addressed a number of shortcomings with this plug-in.

In a blog posting Tuesday, Google listed some popular Outlook add-ons and features that remain off-limits to Apps, even with the new sync tool.

"Unfortunately, some plug-ins don't yet work with Google Apps Sync for Microsoft Outlook, and we wanted to take this opportunity to highlight a few of the more common ones: Microsoft Office Outlook Connector, Acrobat PDF Maker Toolbar, Outlook Change Notifier," reads the Google posting.

To continue using any of these plug-ins, users have to uninstall the Google sync tool.

In addition, Apps Sync for Outlook doesn't play well with programs that interact directly with the Outlook data file, such as Windows Desktop Search and PGP.com's encryption plug-in.

Specifically, Windows Desktop Search will not properly index Google Apps Sync data files. "So in order to stop indexing from running indefinitely, the Google Apps Sync installer disables it. We recommend using the default Outlook search," Google said.

Once again, to re-enable Windows Desktop Search for Outlook data files, users have to uninstall the Google sync tool, but there's a caveat: People using version 1.0.22.1945 or lower of the Google tool must first install the latest version and then uninstall it to re-enable indexing.

"We're working with Microsoft and other partners to help fix these issues and support additional Outlook features like multiple calendars. We'll keep you posted on our progress," Google's posting reads.

Last week, several industry analysts recommended that enterprises do their homework regarding the new sync tool, because it can't fully replicate in Gmail the experience of using Outlook with the Exchange server.

The Burton Group's Guy Creese pointed out in a blog post that the Google plug-in currently doesn't support Outlook features like tasks and notes, and that IT managers should tread carefully if they have special filters and custom templates in their Outlook deployments. "For workers wedded to using every feature in Outlook, the Google solution is still insufficient," Creese wrote.

In a research note, Gartner analysts Matt Cain and Tom Austin said that companies that use Exchange and are considering moving to Apps' Gmail should first do a "stress test" of the sync tool and then do "a widespread pilot."

"We expect that Sync for Microsoft Outlook will have incomplete functions and that users will resist moving from Outlook to the Gmail client, thereby pressuring Google to fill in the functional gaps," they wrote.