Audio waveforms disappearing

I've noticed a huge amount of posts about this and never seen any fixes so far so figured I'd ask here to see if anyone has found a way around it? It will just randomly happen sometimes to projects and the waveform won't show again no matter what I do...

It's not a constant thing and if I drag the audio back from the bins on to the project it will have a waveform, but I can't really do that after editing a huge chunk of it and it causes a headache to edit the rest

Aah! So my cache location didn't exist, I updated it to a new location and it worked, just in case anyone stumbles on this from google!