Colons / special chars within subject were replaced with forward slash

Hi Community,

I am using mac and em client version 10.1.4828 (9843340). In my workflow it is needed to drag and drop mails directly into a browser window which uploaded mail into a documentation system. So far so good.

Mails with are already replied are tagged with a "RE: ", "AW: " and for "FW: " in front of subject line. Normal behavior. Those mails I am not able to upload in my browser windows because of colon in subject line. Maybe a mac-thing and/or of my application. No issue so far.

Now I want to save mail out of em client with right click and “save as …”. I do not change anything but filename colon is replaced with a slash.

Is there a way to manipulate the filename used in case of drag & drop or save-function?

Thanks in advance!

Regards,
Thomas