Backup applications for 32-bit versions of Windows may experience problems on 64-bit versions of Windows

Backup software applications that were developed for 32-bit versions of Microsoft Windows may experience problems when they back up data on computers that are running 64-bit versions of Windows. For example, Microsoft Windows Server 2003 x64 Editions and Microsoft Windows XP 64-Bit Edition for Itanium-based Systems are 64-bit versions of Windows. Most earlier versions of Windows XP and Windows Server are 32-bit versions of Windows.

Data loss and system corruption may occur if a 32-bit backup application is used to back up and restore data on a computer that is running a 64-bit version of Windows.

You should only use 64-bit versions of backup applications when your computer is running on a 64-bit version of Windows. Many backup software vendors have already developed 64-bit versions of their backup applications.

Directly contact the support services of your backup software vendor to determine the availability of 64-bit versions of their backup products. Microsoft cannot provide this information through Microsoft Product Support Services.

Backup software applications must be updated to work with 64-bit versions of Windows. Backup software vendors must for this to deal with changes in how system files and settings are accessed and other internal changes.

Backup applications that only work with 32-bit versions of Windows will not correctly back up user data, system files, and system settings. During a restore operation, these applications may cause irreversible data loss and system corruption.

For more information about 64-bit versions of Windows, visit the following Microsoft Web pages:

The following technical issues are known to Microsoft as potential sources of problems when you use a 32-bit backup application on a computer that is running a 64-bit version of Windows:

• Automated System Recovery (ASR) may possibly create a backup that is not restorable when it is called by a 32-bit backup application in a 64-bit version of Windows. To prevent 32-bit backup applications from creating corrupted system state backups on 64-bit versions of Windows, ASR in those versions of Windows will specifically block 32-bit backup applications from running.
• The Volume Shadow Copy Service (VSS) functionality is different in Windows XP for 32-bit systems and in Windows XP for 64-bit systems. If a software vendor has a backup application for Windows XP that uses the 32-bit VSS interface, the backup application must be modified to use the VSS interfaces in Windows XP for 64-bit systems. The interfaces are similar to the VSS interfaces that are Windows Server 2003.
• System files are virtualized by using a file system filter driver. The 32-bit backup applications will not choose the right version of system files to do the following:
  • Copy to backup media.
  • Use as libraries or executable files as part of the backup process.
  Files in the C:\Windows\System32 folder and other files are affected by this virtualization. Only a 64-bit native backup application can correctly access the 64-bit versions of system files.