Computers only do what you tell them, right? Somebody needs to have a talk with Exchange and Outlook about how they work with resource mailboxes. Every resource mailbox I configure seems to behave differently. Here are two problems I saw this week:

You don’t have appropriate permission to perform this operation.

Except that you do. In this case, I had created a new resource mailbox a couple of days before, configured the delegates, and gave the delegates Full Access permissions to the mailbox. (Unlike with other types of mailboxes, granting Full Access permissions does not prompt Outlook to open the resource mailbox automatically. You still have to add the calendar.) When the delegates tried to open a meeting scheduled by another delegate or when they tried to create a meeting directly in the calendar, they would get this error. No amount of fiddling with mailbox or folder permissions helped and the “/cleanfreebusy” switch no longer works in Outlook 2013. Everything seemed to work as intended in OWA. The fix was easy, but far from obvious. Repair the email account in Account Settings and restart Outlook.

Outlook starts in offline mode after removing a resource mailbox

After removing another user as a delegate on a resource mailbox and removing the mailbox from his Outlook client, Outlook would only start in Offline Mode. He could go online without a problem, but next time he started Outlook, it would be offline again. Repairing the email account didn’t fix this problem. The solution was to delete these two folders after backing up any .pst files in them:

• %appdata%\Microsoft\Outlook
• %localappdata%\Microsoft\Outlook

If Outlook is in cached mode, it will have to download all of the data from the server, which could take a while, depending on the user’s mailbox size and how much data is being cached. This will also erase Outlook’s AutoComplete cache, but I continually tell my users not to rely on AutoComplete as an address book. If they want to keep an address, they should save it to their Contacts. After doing this, the default signatures for new messages and replies had to be reselected. Not recreated, just reselected.

There is something about resource mailboxes that really messes with Outlook’s head. They’re great tools, but you have to verify everything because their behavior is so inconsistent.