Disk Utility - Reinstall Mac OS.
Hello All.
When booting up my 2010 Mac Pro in Recovery Mode and selecting Reinstall Mac OS, will it erase the whole Hard Drive or will it leave alone the files I have saved in there and just reinstall the Operating System please?
I keep getting the Prohibitive Symbol on Boot Up and it's worrying me.
Many thanks,
Mac Pro, macOS Sierra (10.12.6), Mid 2010.