Exchange 2007 - Free/Busy not updating

Open PowerShell and use the following command:

Get-PublicFolder -Server yourservername "\non_ipm_subtree\SCHEDULE+ FREE BUSY" -recurve | Format-List

Run the following commands if you wish to add the replicas:

Set-PublicFolder -Identity "\NON_IPM_SUBTREE\SCHEDULE+ FREE BUSY\EX:/o=Company/ou=First Administrative Group" -Replicas "exchsrvr\Public Folder Database"

Set-PublicFolder -Identity "\NON_IPM_SUBTREE\SCHEDULE+ FREE BUSY\EX:/o=Company/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)" -Replicas "exchsrvr\Public Folder Database"

Once done:

OUTLOOK.EXE /cleanfreebusy (this will force Outlook to update immediately instead of waiting to be updated)