when saving all attachments to a directory, where one/some/all of them are 
already in, there is a dialogue box asking to overwrite the file.

1. The name of the file, which is going to be overwritten, is not mentioned 
in the box. If some of the files should be overwritten and some not, it's 
hard to guess when to say yes.

2. The answer "No" does not cancel saving this particular file, but every 
file after this, too - even if all other do not exist in the directory.