Question

Could anyone sue you if you were to market a program that could import the .mus file type?

Answer 1

Yes, it's very likely that you could be sued but not for using files with the .mus file extension. I think what you mean by importing is being able to read Finale files? This involves the Finale file encoding meaning that you are using their technology. You should first ask for or buy a permit to use this. However, this does not really apply to freeware.

Answer 2

open office can save and open all microsoft office files, and gimp does the same for all picture formats. Same thing for all of the different zip programs out there. I would say the only problem that you will run into will happen when you start messing with dvd content scramble system decrypting (css)

Answer 3

Depends. If you market it as freeware, you probably won't get sued if you attach a good disclaimer that specifies that the product is freeware. If you market it as commercial software you should consult a legal expert knowledgeable in software development law.

To learn more, MIT has a course on copyright law in their OpenCourseWare.

6.912 Introduction to Copyright Law
http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-912-introduction-to-copyright-law-january-iap-2006/

Answer 4

would donations from a freeware product attract lawsuits?