Mail crashes every single day
Q Since I updated to OS X 10.9.4, my Mac has crashed at least once a day. Mail seems the worst and crashes almost every time I try to open it. I have resorted to using webmail, but even if I don’t open Mail, my Mac still falls over every hour or so. How long will it be before Apple releases 10.9.5 to fix the problem? Marcus Stepney
A This isn’t 10.9.4, it’s your Mac. The crash logs you sent me contain lots of messages saying things like “kernel: disk0s2: I/O error”. That looks a lot like a failing hard disk to me. Open Disk Utility and click on the hard disk icon (not the Macintosh HD volume icon beneath it). If the S.M.A.R.T. Status shows failing, then you should definitely back up your data as soon as possible and replace the drive.
Sometimes hard disks fail catastrophically and your Mac simply refuses to boot. In that case, standard operating procedure is to replace the failed drive, or add a fast external drive, and restore your last full disk image. This is a complete bootable image of your hard disk that you previously made with disk cloning software such as Super Duper! or Carbon Copy Cloner. But a drive that is failing progressively, like yours, might well have corrupted some of the kernel files. In particular, when you were updating to 10.9.4, lots of important system files were overwritten and a file corruption at this point could easily account for the errors.
In this situation, the risk is that your backup also contains corrupted files and you just end up recreating your problems. So it’s better to restart with ç+R held to enter Recovery Mode and reinstall a fresh copy of Mavericks on the new drive, then restore your documents and data. If you don’t have a recent Time Machine backup to restore from, you’ll just have to copy as much as you can from the failing drive.
If Disk Utility starts throwing up lots of errors, it might be time to replace your hard disk.