Ran across this just now on both my platforms after noticing 'Backup Method' and 'Backup Comment' were missing in my Explorer windows and were no longer showing up under 'More...' as a choice for column headings.

Apparently a common problem after certain updates that will wipe out Macrium's shell extensions and / or context menus. This article mentions an in-place upgrade as the cause, and yet I've never done one since my clean install of 2004 in May after which I specifically set these columns. Can't say for certain if it was from this update or not, having just noticed it.

Macrium Reflect KnowledgeBase - Windows Explorer context menus and/or shell extensions are missing

Fix is pretty straight forward:

From an elevated Cmd prompt:

CD "c:\program files\macrium\reflect"
regsvr32 RContextMenu.dll
regsvr32 RShellEx.dll

Afterwards either reboot, or stop and start 'explorer.exe'