Brad followed up via email:
Hi David, thanks for your reply. I have followed your instruction and indeed it has frozen during the disk verification process. Bravo! So I let it just run, and after a few moments the ‘repair disk’ window became live. After letting that run, it transpires that I need to reformat the disk. I have backups in Time Machine on a separate drive, so can you advise what I should do next?
And my response:
Hey Brad,
What I’d advise you to do is get a new hard drive right away. You’re fortunate you made it this far. Yes, there are instances where reformatting a drive can help, but the vast majority of the time low-level hard drive corruption is a problem that will return with a vengeance.
You’re going to have to restore your stuff from a backup whether you choose to replace the hard drive now or not, and it’s not something you’re going to want to have to do twice. Get that problem hard drive out of there and fire in a new one – it will make your life a whole lot easier.
Apple stores can do it but they’re expensive. If you’re looking for a cheaper third-party alternative to do it for you, I recommend iResq. If you’re tech savvy and don’t mind diving in yourself, pick up a hard drive from Amazon and use the guides at iFixit to walk through the process. I’m willing to bet you have a non-retina MacBook Pro.
I highly recommend switching to an SSD – you’d see a huge increase in speed. I highly recommend this Samsung SSD on Amazon. I used one a few years ago to upgrade my white MacBook – what a difference! Any way you choose to go is fine, as long as you get that hard drive out of there.
All the best,
David P.