The default is to not delete content that MMW doesn't have. If you on turn the delete content on device but not on phone, the default is to ask for confirmation. That said, it would probably be better to make sure that if you use MMW for audio only, that it will not try to delete videos from the device even if delete content is turned on. I have not checked whether this would happen as I don't have video content on my phone.

EDIT: FWIW, there is an option for either deleting all content not selected in MMW or just that which is in the library (leaving content on the device if it is not in the library).

Rumbelstilzchen wrote:please let us specify the directories MMA ist allowed to read from and write to.

You already can at Options tab > File locations

Hi,
may it be, that MMA has deleted all my videos taken with camera on my smartphone during the sync process? If so, please let us specify the directories MMA ist allowed to read from and write to.