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Inmy Windows server 2008 R2 OS in the Event Viewer there is an error pertains as Microsoft-Exchange-HighAvailability Error ID 121 States-(The description of Event ID 121 from source Microsoft-Exchange-HighAvailability be found.Either the component raises this event is not installed on your local computer or the installation is corrupted.You can install or repair the component on the local computer. If the event is originated in another computer,the display information have to be saved with the event. The following information was included with the event: 752040a1-fad5-48a1-a5bd-2eb4abbd9fe9 Microsoft.Mapi.MapiExceptionJetErrorlog Files Missing or Corrupt: MapiExceptionJetErrorRequiredLog Files Missing:Unable to Mount Database.(hr=0x80004005, ec=543) at Microasoft.Mapi.MapiExceptionHelper.ThrowIfError (String message,Int32 hresult,SafeExInterface Handle iUnknown,Exception inner Exception) at Microsoft.Mapi.ExRpcAdmin.MountDatabase (Guid guidStorageGroup,Guid guidMdb,Int32UlFlags) at Microsoft.Exchange Cluster.ActiveManagerServer.AmStoreHelper.Mount(Guid mdbguid,MountFlags flags) at Microsoft.Exchange.Cluster.ActiveManagerServer.ActiveManagerCore.<>c_Display Classb.<MountDatabase Direct>b_20 at Microsoft.Exchange.Cluster.Replay.Failover performance TrackerBase 1.RunTimedOperation (TOpCode opCode,Action operation) at Microsoft.Exchange.Cluster.ActiveManagerServer,ActiveManagerCore,MountDataBaseDirect (Guid Mdbguid,MountFlags storeFlags,Am MountFlags am MountFlags,AmDbActionCode action code) at Microsoft.Exchange.Cluster.ActiveManagerServer.AmRpcServer.<>c_Display class19.<MountDatabaseDirect>b_180 at microsoft.Exchange.Data.Storage.ClusterHaRpcExceptionWrapperBase, 2.RunRpcServerOperation(String Database Name,RpcServer Operation rpc Operation). What is this error? And What is the remedy for this error?MumthazMuhsin