Cyberduck

Though you can easily move your spectra with a USB memory stick, the ancient FTP protocol is still the most popular way to transfer data from the spectrometer to the PC (or laptop) where processing is performed.
When I started my first NMR experimentations, FTP was not available: local networks were extremely rare and the spectrometers didn't even contain an operating system. So you can guess I have used many FTP clients in my life. During the last 6 years, however, I have been using Cyberduck exclusively, not just because it's free (actually I donated my shareware fee long ago), but because it never fails. It's also very easy to use: the icon gives the exact idea of the complexity of this program.
Over the decades I have always received the question: "Why can't I open my spectra on my PC/Mac?". The last time it happened was this morning. The first thing I say is: "Check your FTP client", because this is the most common cause of the trouble. The second thing I say is "Switch to a SERIOUS program like Cyberduck" (I wonder what they think about the icon). Most of the times I discover that the other guy is using "Filezilla", something that I have never seen but must be a terrible piece of crap, considering the countless troubles it has caused along the years. Nobody ever thinks about the FTP client; the innocent NMR program is the one the receives the blame, instead.
When you are using the wrong client, or the right client with the wrong settings, your files arrive with a different size (this fact alone should ring a bell) or with some bytes changed. One of the great things about Cyberduck is that you don't have to care about settings. It just works out of the box.