The error can be found in the file SAgent.Service_vX.X.X.log in the application folders: "C:\ProgramData\Online Backup and Recovery Manager\Logs" or "C:\ProgramData\SOS Online Backup\Logs": << ERROR Agent - System.Runtime.InteropServices.COMException (0x80042318): Exception from HRESULT: 0x80042318 at Alphaleonis.Win32.Vss.WaitCheckAndReleaseVssAsyncOperation(IVssAsync* pAsync) at Alphaleonis.Win32.Vss.VssBackupComponents.GatherWriterMetadata() at SOSOnlineBackup.Client.Library.Core.ShadowCopy.VssBackup.Init(IVssImplementation VSSImpl) at SOSOnlineBackup.Client.Library.Core.ShadowCopy.VssBackup..ctor(Boolean componentMode, Guid VSSWriterId) at SOSOnlineBackup.SAgent.MSSql.MSSqlBackupPerformer.RunBackup() at SOSOnlineBackup.SAgent.Agent.#=qmgPA_v29nwyXxtvLf9bzHg==(IBackupSession #=qXhnlys\$fBQFZDxm9B0T8qQ==) > > Usually, the error code appears in Event Viewer According to the KBA: Restarting the following VSS services may correct the issue: COM+ Event System Microsoft Software Shadow Copy Provider Windows Management Instrumentation Volume Shadow Copy Sometimes, re-registering the following VSS DLLs from a command line prompt will help resolve VSS problems (requires reboot). cd %systemroot%\system32 net stop VSS net stop swprv regsvr32 /s ole32.dll regsvr32 /s VSS_ps.dll regsvr32 /s oleaut32.dll VSSvc /register regsvr32 /s /i swprv.dll regsvr32 /s /i eventcls.dll regsvr32 /s es.dll regsvr32 /s stdprov.dll regsvr32 /s VSSui.dll regsvr32 /s msxml.dll regsvr32 /s msxml3.dll regsvr32 /s msxml4.dll net start swprv net start VSS Once the DLLs are registered, reboot the server. If any DLL cannot be registered, reboot the server and register the DLL again. For more information please follow the link: