After running Windows update on a Lync 2010 edge server I was unable to communicate with external contacts. I could see their presence but no chat/video or audio. The eventlog contained lots of event 1001 “Information”(Why not error !!!!!) that RTCHOST.EXE crashed. Probably failed installation of KB2982385.
I know the situation, Your are using OWA, ActiveSync or Outlook (in online mode) to search for an old email. Your search request only returns new emails even though you can browse old emails. Now there is a good chance that mailbox database index has gone corrupt. You could do a check by running Test-ExchangeSearch but this might not return an error even though the index is corrupt.
What can I do to fix this problem?