File System Task gives "Could not find a part of the path." when setting a TargetServerVersion back to 2014

I have created a package in VS2017 but then had to change it to use TargetServerVersion 2014.
When in 2017 my File System Task works. When changing to 2014 I get "Could not find a part of the path." error when running the package.
I am using a variable to specify the path and if I copy the variable contents that points to a file I am able to open the file it points to when putting it into Run (Txt file).
So... works in 2017 mode but not TargetServerVersion 2014.
I also retried deleting the File System Task and recreating it but the problem stays.

Any ideas?

So. it would seem that for 2017 you can have the path and files name in your destination, but not in 2014. Only path for 2014