Do I really need to do a full backup every time?

This week, I ran Norton 360 backup for the first time. It took almost 3 full days to backup about 400GB to an external HD (which seemed excessive to me). When it finally finished, I changed one tiny character on one Excel file, just to see how long it would take to run the backup again with one changed file. I just started it, and it looks like the whole process is starting from scratch! It's now 30 minutes later and it's saying I've backed up less than 1%, even though there are virtually no changes since the first time I ran the backup.

 

Can it really be that I need to do a 3-day backup every time? Can Norton 360 do an incremental or some other way? I can't find a setting. Thanks.

This week, I ran Norton 360 backup for the first time. It took almost 3 full days to backup about 400GB to an external HD (which seemed excessive to me). When it finally finished, I changed one tiny character on one Excel file, just to see how long it would take to run the backup again with one changed file. I just started it, and it looks like the whole process is starting from scratch! It's now 30 minutes later and it's saying I've backed up less than 1%, even though there are virtually no changes since the first time I ran the backup.

 

Can it really be that I need to do a 3-day backup every time? Can Norton 360 do an incremental or some other way? I can't find a setting. Thanks.