It may take up to 5 minutes after ERM adds/updates/removes a meeting from the resource calendar before Exchange polls the System Attendant mailbox for free/busy messages. There can be additional delays for this information to replicate to the Exchange server utilized by end-users when viewing free/busy information.
If this information is slow to appear, it is possible to change the polling interval used by the Exchange server’s polling interval by adding the following registry key Exchange server hosting ERM:
PollingInterval (DWORD: seconds)
Location: SYSTEM\CurrentControlSet\Services\MSExchangeFBPublish\
Parameters\<VM name>
Description:
This is the periodic interval used by polling thread to poll the SA mailbox for f/b messages.
Any value < 30 is defaulted to 30 seconds. Default is 300 (5 minutes)
Unlike Outlook, which physically pushes out free/busy information, applications built on CDO utilize Exchange to poll for updates to this information.