Recently I've discovered that my backup system it flawed: there are situation where various files/folders are missed.

I do my backup from local disk to a network NAS.
I use Cobian backup, and I have setup the backup software to create one full backup every week, and one differential backup every day.

Now, the backup software (to my knowledge any backup software work this way) decide the files that go in the differential backup by looking at the file archive attribute. If the attribute is set, then the file go in to the backup.
Now, when you move a file to a new location, on Windows systems, the archive attribute get set and the file is included in the backup, and that's fine...
but when you move an entire folder, no archive attribute is set, nor on the folder, nor in any files inside the folder, so the moved folder isn't included in the differential backup!

So, if you have a full backup plus a differential backup, and you moved folders around... then it's impossible to reconstruct the original files/folders structure starting from the full+differential backup, because the backup software didn't include the moved folders in the differential backup.

So my differential backup are useless...

Why does windows set the archive attribute when moving a file, but not when moving a folder?

How can I deal with this issue?
Is there a way to create a differential backup that works as it's supposed to do?

Doing full backup every day is not practical, because the changed data is about 0.1% at day (by using a differential backup I can keep 4 weeks of files history without using too much disk space.)