Note This topic applies to Windows Vista, Windows Server 2008, and later. For information about Windows Server 2003, see Backing Up and Restoring System State in Windows Server 2003 R2 and Windows Server 2003 SP1
When performing a VSS backup or restore, the Windows system state is defined as being a collection of several key operating system elements and their files. These elements should always be treated as a unit by backup and restore operations.
Note Microsoft does not provide developer or IT professional technical support for implementing online system state restores on Windows (all releases).
When backing up and recovering system state, the recommended strategy is to back up and recover the system and boot volumes in addition to the files enumerated by the system state writers.
Note System state writers are writers that have the VSS_USAGE_TYPE attribute set to either VSS_UT_BOOTABLESYSTEMSTATE or VSS_UT_SYSTEMSERVICE.
In addition to the enumerated operating system and driver binary files that are enumerated by the system state writers, there are certain other files that must be backed up as part of system state.
Backup programs should also set the LastRestoreId registry key. For more information, see Registry Keys and Values for Backup and Restore.
Note In Windows Vista, Windows Server 2008, and later, the names and locations of some system files have been changed as follows.
Licensing Files
The following files are required for licensing and must be backed up:
%windir%\system32\*.C7483456-A289-439d-8115-601632D005A0
The following rules must be followed when system state is restored:
- For an online (safe mode or full operating system) restore, the copies of these files that are already on disk should be preserved. In other words, do not restore these files from the backup media.
- For an offline (Windows Recovery Environment or Windows PE) restore, replace the files on disk with the ones from the backup media.
Performance Counter Configuration Files
The performance counter configuration files are located in the %SystemRoot%\System32\ directory and have the following names:
- Perf?00?.dat
- Perfc0??.dat
- Perfd0??.dat
- Perfh0??.dat
- Perfi0??.dat
- Prfc0???.dat
- Prfd0???.dat
- Prfh0???.dat
- Prfi0???.dat
These files are only modified during application installation and should be backed up and restored during system state backups and restores.
IIS Configuration Files
Note In Windows Vista with Service Pack 1 (SP1) and later, you should not back up these files. Instead, use the in-box IIS configuration writer. For more information about this writer, see In-Box VSS Writers.
The relevant IIS configuration files and their locations are listed below:
- The .NET FX machine.config file is located in the framework version directory.
- The ASP.NET root web.config file is located in the framework version directory.
Note The configuration files for both .NET FX and ASP.NET are in the framework version directory. If multiple versions of the framework are installed on the computer, this directory will contain one configuration file for each installed version.
- The IIS applicationHost.config central configuration file is located in the %windir%\system32\inetsrv\config directory. For the server to understand this configuration file, there are schema files that determine its grammar and structure. These files are located in the %windir%\system32\inetsrv\config\schema directory.
The framework version directory path is stored in the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\InstallRoot
In addition, the following cryptography keys must be backed up:
- %ProgramData%\Microsoft\Crypto\RSA\MachineKeys\*
- %SystemRoot%\System32\Microsoft\Protect\*
Framework Files
All versions of the .NET framework must be backed up. The files are located in one or both of the following directories:
- %windir%\Microsoft.Net\Framework
- %windir%\Microsoft.Net\Framework64
In addition, the assembly files must be backed up. These files are located in the following directory:
- %windir%\assembly
Task Scheduler Task Files
The task scheduler's task files must be backed up. The files are located in one or both of the following locations:
- %windir%\system32\tasks and any subdirectories (recursively)
- %windir%\tasks (no subdirectories)
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Build date: 2/3/2012