Apple Store Diagnostics say my hard drive failed but my computer works fine - Should I replace it? I had my MacBook Pro 17", late 2011, in for a replacement of the motherboard. The technician in the Apple Store told me that their diagnostics said that not only my mainboard had failed, but also both my hard drives (SSD and HDD in SuperDrive slot). I asked them to NOT replace the hard drives. When I got the laptop back, I can boot up normally and all my data is still there and accessible. Should I nonetheless replace my hard drive? Is there any possible damage the hard drives could have that I can't see, despite them working from what I can see?

Thank you!
First and foremost make sure you have a backup regime in place (e.g. using Time Machine).

Also, ensure you're backing up both the SSD and HDD. 

My answers to your questions below assume you do have backups in place!


  Should I nonetheless replace my hard drive?


You're asking for an opinion here, so you risk getting different answers. However, if it was me I'd test both the hard drive and SSD with something better than Disk Utility (but that's easy for me to do as I own a whole range of diagnostic packages). In fact I'd test both of them at least twice, using different software.

Then, assuming all was okay, I'd likely replace the HDD with a fusion/hybrid drive and put the existing HDD in an external enclosure.


  Is there any possible damage the hard drives could have that I can't
  see, despite them working from what I can see?


Yes.