This is a pre-T2 Mac so your only option for a properly clean install is to boot an external disk containing the latest macOS installer for your model or, if you can get some sighted help and the process still works, using Internet Recovery. Happily there are absolutely no restrictions in doing this, so simply download, use a Terminal command to build the installer, boot your Mac from it, then use Disk Utility to completely erase the internal disk (not just the volume, you must show all devices in the view menu and erase the outer disk with a GPT partition scheme) and then use the installer to install the latest supported macOS. You will then have a completely clean Mac.
Google will furnish the relevant support docs and general commentary but if you need further help, feel free to ask and I’ll give you more detail. -- The following information is important for all members of the Mac Visionaries list. If you have any questions or concerns about the running of this list, or if you feel that a member's post is inappropriate, please contact the owners or moderators directly rather than posting on the list itself. Your Mac Visionaries list moderator is Mark Taylor. You can reach mark at: mk...@ucla.edu and your owner is Cara Quinn - you can reach Cara at caraqu...@caraquinn.com The archives for this list can be searched at: http://www.mail-archive.com/macvisionaries@googlegroups.com/ --- You received this message because you are subscribed to the Google Groups "MacVisionaries" group. To unsubscribe from this group and stop receiving emails from it, send an email to macvisionaries+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/macvisionaries/5D2BDD84-3B97-449D-9B5E-DF50F52E2C2E%40me.com.
