I had a case recently in which the end user couldn’t add any resource calendars to Outlook. Every time she tried, she would get this error message:

“The connection to Microsoft Exchange is unavailable. Outlook must be online or connected to complete this action.”

Which was curious because the Outlook status bar said it was connected and she was able to send and receive emails.

I opened Outlook Connection Status (ctrl-right-click on the Outlook icon in the system tray and select Connection Status), and everything looked normal until I attempted to add a room calendar (click Open Calendar then select “From Room List”). A couple of new lines with a Type of Directory appeared in the Outlook Connection Status window. Their statuses went from Establishing to Disconnected, back to Establishing, then to Disconnected again.

I deleted her cached directory data (%appdata%\Microsoft\Outlook) and retried. Same thing. Next, I told Outlook to download the offline address book (File tab > Account Settings > Download Address Book), fully expecting that to error out also. Except that it didn’t.

When the OAB had finished downloading, I noticed that the two Directory listings in Outlook Connection Status both said Established. I then went back to the calendar tab and added a room with no problem.

If I discover more about what the problem was, I’ll update this post. In the meantime, projects await…

Update 4/28/2015 – Another client on the same Exchange organization was unable to edit a distribution group in Outlook. When she opened the properties window of the group, the membership box was empty and the Update button was grayed out. After she manually updated her Offline Address Book, she was able to view and update the group membership.