I have set up a daily incremental backup to a network drive.
On the first day it worked perfectly, performing the initial full backup to the network drive.
On the second day it attempted an incremental backup, seemed to find the parent backup file OK, but then failed with error code 90 on trying to commence the incremental backup.
On the third day it once again perfomed a full backup, replacing the original file.
On the fourth day it again attempted an incremental backup, and again failed with error code 90.
… and so on …
This is OK, up to a point – I have a backup on my network that is no more than two days old. But I would really like to move to internet backup, and one of my current objectives is to work out what the bandwidth requirements will be for this.