USB need to be format

Hello, To the person who may solve my question,

hello i put a usb in another computer of mine and it reads it then i put files or songs on it but one thing is when i put it in my main computer it say's, "You need to format the disk in drive K: before you can use it but when i did use it ages ago it was on the main computer" and i added songs on it but now it say i have to format it now is there a way i can get access to my stuff from my main computer.

Thanks, Gervarod