Hi StuartR,
The reference manual (v1.20) states ....
"If the total size of the target data for backup exceeds 3.9Gb (excluding Audio files), the backup function is not available."
(before 1.20 it used to be 1.9 GB - according to the reference manual of 1.10)
So it seems to have doubled ...
I have not actually tried it though.
Regards
Rudy