Turning on your iMac only to discover that it’s displaying a flashing question mark can induce that sinking feeling in most users. This especially true if you have not recently performed a backup of your system.
Typically, the flashing question mark appears when there is a problem with your iMac’s hard disk. Many users encountering this problem will often attempt to use the “command + R” in order to initiate a reinstallation of their operating system. Unfortunately, this rarely fixes the issue and often just compounds the problem.
In a substantial number of cases when the “flashing question mark” appears the underlying problem is a failed or failing hard disk. Your disk might have bad sectors, firmware problems, read-write head problems or PCB (printed circuit board) issues. When your iMac looks for the files needed to boot your system up – it cannot find them. Hence, your iMac will display the “flashing question mark” icon.
Only last week, we helped a Dublin medical practice with this problem. Their iMac, which they used in their reception area, displayed this rather unwelcome screen. The last Time Machine backup which they had performed was well over two months ago. Our diagnosis revealed a failed S-ATA hard disk in their 2013 21.5” iMac. The problem being extensive bad sectors (14,591 in total) and a corrupt HFS+ disk volume. We were able to perform a complete data recovery for them.
The lesson as always in these cases, is backup, backup and more backup. We set them up with a robust, automated and GDPR-compliant backup solution so this problem would never be repeated.