KLS Backup is available in both 32-bit and 64-bit editions. The 32-bit edition is the default because it is the most compatible with operating systems, add-ons, and third-party tools. However, the 32-bit edition also includes the 64-bit backup engine, therefore, it can run backup, synchronization and restore jobs in native 64-bit mode.

To select between the available architectures, use the 'Use the 64-bit client to run the job' option (available on the profile's Options page). This option is available only in the 32-bit edition of KLS Backup, because the 64-bit edition runs exclusively in 64-bit mode.