I have a PC Laptop, Windows 10, and use the Line 6 Toneport UX2 interface. I can record tracks just fine and get strong levels. When I play it back it sounds "wavy" like a heavy weird affect has been applied. It also cuts in and out during playback. I have applied the most recent driver for the Toneport. Any ideas?
How are you monitoring playback of your tracks, through the Toneport or direct from the computer speakers? If the former, you need to check whether the interface is somehow applying, what sounds like from your description, a "flange" effect. If playback is via your computer speakers, you need to check that Windows Sound Settings is not "getting in the way". Depending which audio driver type you are using it is entirely possible that Windows Sounds could also be affecting the output from your Toneport.