private static MapiStream OpenAndLockStream(MapiFolder oofHistoryFolder, byte[] initialBytes, long hashCode, out bool isNew) { MapiStream mapiStream = null; isNew = false; OpenPropertyFlags openPropertyFlags = OpenPropertyFlags.Modify | OpenPropertyFlags.DeferredErrors; try { mapiStream = oofHistoryFolder.OpenStream(PropTag.OofHistory, openPropertyFlags); OofHistory.LockStreamWithRetry(mapiStream, hashCode); } catch (MapiExceptionNotFound) { if (mapiStream != null) { mapiStream.Dispose(); mapiStream = null; } OofHistory.Tracer.TraceDebug(hashCode, "OOF history property does not exist, trying to open with create flag."); openPropertyFlags |= OpenPropertyFlags.Create; mapiStream = oofHistoryFolder.OpenStream(PropTag.OofHistory, openPropertyFlags); OofHistory.LockStreamWithRetry(mapiStream, hashCode); OofHistory.ResetOofHistoryProperty(mapiStream, initialBytes, hashCode); isNew = true; } return(mapiStream); }