The following are excluded from backup on all Windows systems:
- Browser caches - temporary internet files from e.g. Internet Explorer, Firefox, Chrome or Opera.
- Other temporary folders. HFS users who run programs such as Abaqus, which keeps its files in C:\temp, should change the relevant program's default directory setting to ensure that their files are backed up.
- Backups, such as Windows 8.1 File History, NTBackup bkf and ARCserve ctf files.
- Microsoft SQL Server database files.
- BBC iPlayer downloads.
- The Recycle Bin.
- Virtual machines.
- Suspected 'infected' files quarantined by Sophos.
- Outlook cache files (*.ost).
Additionally, for desktop/laptop backups, Windows operating system files are excluded from backup. These include:
- The system files in C:\WINDOWS
- The system files in C:\WINNT
- The system files in *:\Program Files
- The system files in *:\Program Files (x86)
- The Office install files in *:\MSOCache
- The system files saved during an upgrade in *:\Windows.old
- The performance log files in *:\PerfLogs
- Cache and generated files in
- *:\...\All Users\Application Data\Microsoft\Search
- *:\...\All Users\Application Data\Microsoft Help
- *:\...\All Users\Application Data\Microsoft\HelpLibrary
- *:\...\All Users\Application Data\Microsoft\Windows Defender
- *:\...\All Users\Application Data\Apple Computer\Installer Cache
- *:\...\All Users\Application Data\Apple\Installer Cache
- *:\ProgramData\Application Data\Microsoft\Search
- *:\ProgramData\Application Data\Microsoft Help
- *:\ProgramData\Application Data\Microsoft\HelpLibrary
- *:\ProgramData\Application Data\Microsoft\Windows Defender
- *:\ProgramData\Application Data\Apple Computer\Installer Cache
- *:\ProgramData\Application Data\Apple\Installer Cache
- *:\...\Application Data\...\Cache
- The TSM installation files in C:\tsm_images, *:\...\tsm-*-win64.exe and *:\...\tsm-*-win32.exe
- The following system files:
- *:\io.sys
- *:\config.sys
- *:\msdos.sys
- *:\pagefile.sys
- *:\hiberfil.sys
- *:\swapfile.sys
- *:\autoexec.bat
- *:\boot.ini
- *:\ntdetect.com
- *:\bootmgr
- *:\ntldr
- System Services
- Background Intelligent Transfer Service (BITS)
- Event logs
- Removable Storage Management Database (RSM)
- Cluster Database (cluster node only)
- Remote Storage Service
- Terminal Server Licensing
- Windows Management Instrumentation (WMI)
- Internet Information Services (IIS) metabase
- Dynamic Host Configuration Protocol (DHCP)
- Windows Internet Name Service (WINS)
- System State
- Active Directory (domain controller only)
- System Volume
- Certificate Server Database
- COM+ database
- Windows Registry
- System and boot files
- ASR - Automated System Recovery
These system files are excluded from backup because, in the event of system failure, they can only be restored to identical hardware (make, model, firmware, hardware and configuration). A restore to dissimilar hardware is not supported by Microsoft, as documented in their Knowledge Base.
After a system failure, we recommend that Windows operating system files are always restored using the original Windows media, or the Recovery/Restore CD/DVD that accompanies your machine.