Some “Note to Self” Research and Tech (mostly for Mac) Stuffs

Tech Troubleshooting

Mac: Problem with the keyboard volume controller

Error/Problem: Volume controller stops working etc.
Solution: If quitting and restarting coreaudiod doesn’t work, use the following command in the Terminal.

sudo kill -9 `ps ax | grep 'coreaudiod' | grep -v grep | awk '{print $1}'`

LaTeX: biber gave return code 2

Error/Problem: For whatever reason, biber or biblatex stopped working with the error “… gave return code 2…”
Solution: Just reset the biber cache via the following command in Terminal (Mac).

rm -Rf "$(biber --cache)"

Ahkab: Problem producing plots in Python3

Error/Problem: Plotting graphs using ahkab in Python3 produces the error “module ‘pylab’ has no attribute ‘hold’”.
Solution: ‘Hold’ for plots is enabled by default on Python3.

  1. First, find out the directory of which ahkab was installed using pip3 list -v.
  2. In the ahkab folder, open Then, look for the lines containing pylab.hold(True) and pylab.hold(False). Either remove them completely or comment them out.
  3. An alternative solution is to use ahkab with Python2. However, this is not encouraged due to the deprecation of Python2 and also the lack of support with most transitting towards Python3.

Adding Windows Network Printer (Mac)

These steps apply for Mac OS X 10.11 El Capitan and later. Adjust accordingly for older versions.

  1. System Preferences -> Printers and Scanners
  2. Click on “+ ” to add a new printer
  3. Select “Advanced” from the top toolbar. If you don’t see it, right-click on the toolbar and select “Customize Toolbar…”. Drag the “Advanced” button into the toolbar.
  4. Under “Type”, choose “Windows printer via spools
  5. Under “Device”, choose “Another Device
  6. Under “URL”, enter “smb://printserver/printername
  7. Enter the “Name” of your printer. “Location” is optional
  8. Use” the “Generic PCL Driver” for El Capitan and newer or “General PCL 6 Driver” for older versions of Mac OS X
  9. Click on the “Add” button
  10. You might be prompted to enter your login credentials. Choose “Registered User”, enter your login username “admin\username” followed by your password
  11. Done. You should be able to use the printer now.

If you ever come across a printing problem with the error message “Hold On Authentication”, you can reset the password to the network printer via the following command in Terminal:

sudo lpadmin -p printername -o auth-info-required=username,password

Startup Key Combos

Macs with Apple Silicon

  1. During startup after restarting your Mac or from a fresh boot, continue to press and hold on the power button.
  2. Release power button when the startup options screen appears.
  3. Window with startup functions similar to Intel-based Macs below will carry you through.

Intel-based Macs

  • Command (⌘)-R: Boot from the built-in macOS Recovery system.
  • Option-Command-R or Shift-Option-Command-R: Boot from macOS Recovery over the internet.
  • Option (⌥) or Alt: Boot to Startup Manager. You can choose options for startup disks via here.
  • Option-Command-P-R: Reset NVRAM or PRAM. This can be used to reset peripherals and devices that have been acting weird, e.g. mouse, keyboard, etc.
  • Shift (⇧): Boot in safe mode.
  • D: Boot to the Apple Diagnostics utility (use Option-D to boot to ADU with internet).
  • Command-V: Boot in verbose mode.