Hi Taurojo,
usually we don't copy the sourcefile to a local drive for processing but instead it just stays where it is. Do you have both services, ffastrans and webinterface installed on the same machine?
Usually working with UNC shares just requires to configure the windows services for webinterface AND ffastrans to run with some credentials/username who has access to the share on your NAS, see bottom of the installation docs:
https://ffastrans.com/wiki/doku.php?id=gui:installation
In webinterface settings, you configure something like that:
STATIC_ALLOWED_BROWSE_LOCATIONS_DISPLAY_NAMES: some_name_of_your_choice
STATIC_ALLOWED_BROWSE_LOCATIONS: \\yourservername\yourshare\
When you submit a job from webinterface this way, the %s_source% variable will be set to the selected file's full unc path, e.g.
\\yourservername\yourshare\file.ext
Now, if your workflow starts with a "Deliver File" processor which is set to copy to a local drive... then: voila, you have now made a copy from UNC share to local drive (but for no good reason maybe?) - and the next processor after Deliver File would work with the local copy.
One alternative way would be to allow the user to upload files and configure the upload location in webinterface settings to be a local drive. This way you also start with a copy of the file on a local drive of the ffastrans server.