I possess an amazing capacity to get myself into trouble, computer trouble to be specific. This time, I found myself unable to run terminal app (macOS High Sierra version 10.13.6) or any of my other processes (VPN, Google Drive, Amazon Drive). I couldn’t even open my text edit app. Sample error message verbiage from within terminal:
I’m responsible for creating the problem in the first place: I modified my sysctl.conf file while installing Postgres SQL and following instructions in a book I purchased. I reproduce the config file here for your review. DON’T USE THESE SETTINGS OR ANY OTHERS UNLESS YOU KNOW WHAT YOU’RE DOING.
Anyway, back to the problem and how I resolved it. I realized I had to neutralize-delete-terminate the wayward config file to get back to normal (or so I hoped.)
Step 1 – I found this article to help me get started: Troubleshoot Your Mac With These Hidden Startup Options. I followed the first two steps, checking hardware and Safe Mode; neither suited my purposes since it wasn’t a hardware problem and Safe Mode didn’t allow me access to my system.
Step 2 – Booting into Single User mode worked perfectly and gave me root access to my system! I proceeded to navigate to and open the offending file using the Nano text editor; changes made and saved NOT!!!! Single User mode permits read-only permission, even as root user! Now what???
Step 3 – Googled again – found this lifeline from WestWind Computing. I followed step 1: fsck -yf. Step 2 caught my eye because it enabled write access to the disk: mount -uw /. I once again opened the conf file in nano and commented out each line, saved the changes successfully and exited Single User Mode. (see modified file below):
Step 4 – Reboot! Mission accomplished, system back to normal.