Defrag and Differential backup ??

[TenOC]

Does the act of running a defrag program either MS or a third party program cause a file to change so that it will be back up as part of the next differential backup?

[TheWeaz]

If you’re doing an image backup, TI only cares about “in use” sectors – not files, changed or otherwise.
A defrag will change the list of in use sectors and, yes, they will be contained in a DIFF backup.

[shieber]

Actually, a defragger can change a sector and then change it back -- something defraggers are prone to do as they swap data in and out of locations -- and ATI will count that as "changed.". Every changed sector would get backed up in the subsequent differential.