If your users are having issues searching Outlook mail after installing Google Apps Sync. This post from Outlook team is for your, as follows:
The Outlook team has recently been made aware of a serious bug / flaw with the recently announced Google Apps Sync for Microsoft Outlook, and as a result we wanted to provide the Outlook user community with additional details around this problem as well as information on how to address it.
The installation of the Google Apps Sync plugin disables Outlook’s ability to search any and all of your Outlook data. When a Google Apps user installs the sync plugin for Outlook, the plugin modifies a registry key which disables Windows Desktop Search from indexing and providing search functionality for all Outlook data, not just the Outlook data being synchronized from GMail. Because Outlook search relies upon the indexing performed by Windows Desktop Search, Outlook search functions are broken as a result. It is also important to note that uninstalling the plugin may not fix the issue.