Hi,

we have a fileserver hosting the home folders for users on our domain. During weekends we do a full backup of the folders that results in about 300 Gb then on monday we do a differential backup and that ends up being about as large. 

The backup method fo the weekend backup is set to "Full - using archive bit (reset archive bit)" and
the backup method for the differential backup is set to "Differential - Back up changed files since last full - Using archive bit (does not reset archive bit)"

The files are stored on two servers that mirror each other using DFS (in case that mattered)

Frankly I dont know what could cause this so I dont know what more technical detail to add.

Best Regards,
Agust Rafnsson.