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We are retroeeks

Essential classic Mac boot key combos

Press this together with Power button

  • Cmd-Option-P-R Reset PRAM.
  • Cmd-Option-Shift-Delete-(#) Boot from a SCSI device on the SCSI bus other than the disk selected in the Startup Disk control panel. The Optionional number allows for booting from a specific SCSI ID.
  • R Force PowerBook to reset screen.
  • C Boot from Apple-brand CD-ROM drive. Works with a few third-party drives too. For drives that can't boot using the C key, try Cmd-Option-Shift-delete as explained above.
  • Hold mouse button Eject floppy and optical drive.

Press this after startup chime plays

  • Command Boot with virtual memory off (System 7 - Mac OS 9.x only).
  • Shift Boot with Extensions, Control Panels, and Startup Items disabled (including VM, if on).
  • Space Open Extensions Manager (System 7.5.x and higher only) on boot.
  • others Check documentation for third-party extensions and control panels; there are often keys to disable these individually.

Press this before Finder starts, after Mac OS logo dissapears

  • Cmd-Option Rebuild the desktop file.
  • Shift Disable Startup Items only.
  • Option Start Finder with no open windows.

The following are some other useful shortcuts/undocumented combos

  • Cmd-Option while opening Memory control panel: allow startup RAM tests to be turned off (Mac OS 8.5 - 9.x only).
  • Cmd-Power Enter NMI, or Macsbug (if installed).
  • Cmd-Option while opening Chooser: rebuild Chooser's cache.


Updated on 18.12.2021