4 
8 Dosdude1 High Sierra Tool
I installed High Sierra using the dosdude patcher tool on my late 2008 MacBook Pro 17 inch. Is there anyway I could go back and reinstall El Capitan which was my original OS version. I tried downloading the installer from the App Store, but it said my Mac OSX version is too new. I also tried going into recovery mode, but it showed the circle with diagonal line through it. I also don’t use time machine. Is there anyway I could go back to El Capitan?
Is dit een goede vraag?
Score
0
971 
Did you flash your EFI chip?
door mayer
The OS installer won’t over-write a newer OS.
Don’t forget APFS could get in the way as well
door Dan
Thanks! Would I put the installer on a drive and boot it after I wipe the actual drive, and how do I wipe all the data off of my Mac?
door Random _User_101
You need to setup an external drive or use the original grey disks that came with your system, or the retail version of the OS (image of one of the great cats on it) Booting up with one of these is the easiest way. You also could connect your Mac to a second Mac via a FireWare cable, then set your system up in Target Disk Mode. This allows your system to look like an external drive to the other Mac. You can then either copy off anything important, make a TimeMachine backup, use Disk Utility from the master Mac and then re-install the OS as you wish to your Mac (target drive) from the other Mac.
door Dan