Hey all. I neglected to disable my Trim Support before booting into Safe Mode, to fix Mail.app that crashed. After sorting out Mail, when I restarted - was met with the grey No Entry sign. Followed the Cindori instructions - but the terminal commands didn't help. As per their suggestion - opted for a reinstall. Not wanting to rely on the Internet method - my broadband is quite slow - tried to reinstall from my USB Yosemite USB installer. After the installer line runs through - a split second takes me to the Select Languages option, but then something goes wrong, and I am taken back to the Recovery screen, which then doesn't react. (I cannot select Internet Recovery). I'm now downloading another Yosemite install file on my Mac Mini, and will try and recreate a fresh USB Installer, to repeat the process. My question - as things stand - how good are my chances of simply installing a fresh OSX, without losing my data? I did a TM Backup over the weekend - but I've done quite a bit since then [facepalm - writing up my dissertation]. Would appreciate some opinions!