I have a simple VSTO outlook addin that needs to move email messages into public folders. It works fine except when outlook is first launched. After a first launch of outlook (office 365 business) if I try and use the addin to move a message into a public folder using GetFolderFromID(IDValueStoredInMyAddin) I get an error "The operation failed. The messaging interfaces have returned an unknown error. If the problem persists, restart Outlook". If after starting outlook the user manually expands the public folders tree then the addin works without this error. Any ideas what is going on here? Is there a way from within a VSTO addin for expand public folders?
