loud hissing noise

When i try to record a new song, the first take is all good…but when i try and add another track the sound of the second take is just loud hissing…this happend out of the blue…everything was good last night…i have the latest version of audacity…please help if you can…thanks…Dave

Can you tell us EXACTLY what you’re doing?

the sound of the second take is just loud hissing

You literally mean JUST hissing, right? No recognizable signal at all?

Are you monitoring yourself while recording? Are you hearing the hiss while recording?

…Full-volume white noise can be caused by a corrupt file (i.e. a hard disk problem) or by opening a compressed audio file as “raw” data, or by opening a raw file with the wrong parameters.

If i start aud. ( a new file) and record a guitar track, all is good…when i try and record another track it shows up as a big wave or signal that does not look anything like a sound signal i usealy get… i listen to exsisting track while recording new track…i dont hear the noise untill i playback the new track. I can load a backing track into aud. and it plays great but if i try to record another trk i get the noise.i use a line 6 usb device(guitarport) to record…all has worked great for several years.all worked last nite (30th) thank you for your help…dave