I had the unfortunate luck of getting the infamous flashing question mark folder when I booted up my 2012 macbook pro. I have never used timemachine before, so I can't call backups. So i've been following a guide I found on apple website that told me how to backup my HDD contents to an external hard drive, as detailed here: https://support.apple.com/en-us/HT204323
I've already followed it to reinstall the Mountain Lion OS on my external HD. But when I got to the migration assistant part to copy my files on HDD to external by selecting "From another disk", it can't find my HDD and is stuck on loop for "select the source".
What should I do to get past this stage? Thanks!