Exchange 2010 Unexpected error (0x79c9729b)

After rebooting my Exchange 2010 server and running Best practice analizer I'm getting the following error and the database is in unknown status:

Unexpected error (0x79c9729b) while executing command 'Get-MailboxdatabaseCopyStatus -Identity 'Mailbox database xxxxx | Filter-PropertyEqualTo -property 'ActiveCopy' -Value $true.



   at Microsoft.Exchange.Configuration.MonadDataProvider.MonadPipelineProxy.ClosePipeline(MonadAsyncResult asyncResult)
   at Microsoft.Exchange.Configuration.MonadDataProvider.MonadPipelineProxy.InternalEndInvoke(IAsyncResult results)
   at Microsoft.PowerShell.HostingTools.PipelineProxyBase.EndInvoke(IAsyncResult results)
   at Microsoft.Exchange.Configuration.MonadDataProvider.MonadCommand.EndExecute(MonadAsyncResult asyncResult)
   at Microsoft.Exchange.Configuration.MonadDataProvider.MonadDataReader.Close()
   at Microsoft.Exchange.Configuration.MonadDataProvider.MonadDataReader.Dispose(Boolean disposing)
   at System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior)
   at System.Data.Common.DbDataAdapter.Fill(DataTable[] dataTables, Int32 startRecord, Int32 maxRecords, IDbCommand command, CommandBehavior behavior)
   at System.Data.Common.DbDataAdapter.Fill(DataTable dataTable)
   at Microsoft.Exchange.Management.SystemManager.WinForms.DatabaseStatusFiller.FillTableWithDatabaseCopyEntries(DataTable table)
   at Microsoft.Exchange.Management.SystemManager.WinForms.DatabaseStatusFiller.OnFill(DataTable table)
   at Microsoft.ManagementGUI.AbstractDataTableFiller.Fill(DataTable table)
   at Microsoft.Exchange.Management.SystemManager.WinForms.MonadDataAdapterExecutionContext.Execute(AbstractDataTableFiller filler, DataTable table, ResultsLoaderProfile profile)
   at Microsoft.Exchange.Management.SystemManager.DataTableLoader.Fill(RefreshRequestEventArgs e)
   at Microsoft.Exchange.Management.SystemManager.DataTableLoader.OnDoRefreshWork(RefreshRequestEventArgs e)
   at Microsoft.Exchange.Management.SystemManager.RefreshableComponent.worker_DoWork(Object sender, DoWorkEventArgs e)
   at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument)

Specified cast is not valid.
   at Microsoft.Exchange.Cluster.Replay.RegistryParameters.<LoadRegistryValues>b__2(RegistryKey key)
   at Microsoft.Exchange.Cluster.Replay.RegistryParameters.TryGetRegistryParameters(Action`1 operation)
   at Microsoft.Exchange.Cluster.Replay.RegistryParameters.get_GetMailboxDatabaseCopyStatusRPCTimeoutInMSec()
   at Microsoft.Exchange.Cluster.Replay.ReplayRpcClientWrapper.GetCopyStatus(String serverName, RpcGetDatabaseCopyStatusFlags collectionFlags, Guid[] dbGuids)
   at Microsoft.Exchange.Management.SystemConfigurationTasks.GetMailboxDatabaseCopyStatus.PrepareStatusEntryFromRpc(Server server, Collection`1 databaseCopies)
   at Microsoft.Exchange.Management.SystemConfigurationTasks.GetMailboxDatabaseCopyStatus.WriteResult[T](IEnumerable`1 dataObjects)
   at Microsoft.Exchange.Configuration.Tasks.GetObjectWithIdentityTaskBase`2.InternalProcessRecord()
   at Microsoft.Exchange.Configuration.Tasks.Task.ProcessRecord()
   at System.Management.Automation.CommandProcessor.ProcessRecord()