I’m having problems trying to formatting my iMac after changing the hard drive, and the Question mark symbol still appearing in the screen, now appears a new one like an Y with a circle ⭕️ in the middle.
What is the exact model of your iMac? You can get this information by entering your system serial number here or here. The serial number can usually be found on the bottom of the iMac stand.
What version of macOS are you trying to install?
A brand new drive is blank with no operating system. If your iMac supports Internet Recovery Mode, then you can boot it and use Disk Utility to erase the new blank drive so it contains a GUID partition formatted as HFS+ (Journaled). Then you can click on the re-install macOS option.
Otherwise you can connect your old drive externally and boot into its local Recovery Partition to format & reinstall macOS.
Another option would be to boot your original drive externally and use Carbon Copy Cloner (CCC) to clone the original drive to the new blank drive. You will first need to use Disk Utility to erase the new drive so it contains a valid macOS partition fthat CCC can use for the destination of the clone.
A "Y" symbol usually means FireWire Target Disk Mode and a circle with a single line through it means the OS you are trying to boot is corrupt or is too old and not compatible with the computer.
Thanks!
What’s the meaning of a Y symbol with a circle in the middle
