1TB Hard Drive issue, Mac

O’ve been using a WD 1TB external hard drive to back my Mac up for the last few year without any problems. Yesterday I transfered my iTunes onto it and which seemed to be working fine, but when I tried to reconnect it this morning i got a ‘The disk you inserted is not readable by this computer’. I’m running OS X 10.6.8, so an older operating system.

Has anyone got any advice? My life is on this hard drive and i need it back.

What’s the model number of your drive?

See if this helps.