We use MS Exchange Server 2003, and have a variety of Outlook versions, mostly 2010 and 2007.

Our company wide shared calendar sat in a public folder, and was also in the favorites folder.

Yesterday, both disappeared, are gone, and I can't figure out where they went, if deleted, or just another instance I'm reading about hear with screwed up Outlook.

No one "did" anything, but now our entire calendar and history are gone!