I own a vintage "LC II" (a.k.a. "Macintosh Performa 400") with System 7.x installed years ago. Unfortunately I'm not able to log in anymore, because after the initial boot the screensaver fires up and locks the screen with a password.

I would like to know either if:

  1. there are any key combinations or such to "unlock" screensaver/log in?

  2. there are any key combinations to "reset things"?

  3. there is a easy–to–follow guide to create installation floppies to re-install from scratch?

  • Do you have access to another machine with a floppy drive? Apple does provide the Mac OS 7.5.3 floppy images and I've used those to do a fresh install before. There's likely a less-drastic solution though. Oct 18, 2012 at 16:03
  • 1
    Does booting with extensions off help? I think you press Shift after it chimes to disable extensions.
    – lhf
    Oct 18, 2012 at 16:46

1 Answer 1


There are a couple options.

lhf is right -- holding down shift will disable all extensions on startup in System 7.x. If you are running OS 7.5, holding the shift key will bring up the extensions manager, allowing you to choose the extension you want to shut off.

If that does not work, you can boot from a disk as if you were going to install software. You can download Mac OS 7.5.3 from Apple. You technically only need the first disk to boot. Once you create the disk from the first image, boot from it by holding down command and option.

That should boot into a very minimal version of System 7.5 and bypass the screensaver.

  • Thanks for your answer. I will try this out ASAP and let you know.
    – Ali
    Oct 19, 2012 at 7:21
  • Jeez, it has been so long! However, today I tried to turn it on while holding down the shift key, but it doesn't seem to do much. After many years there might be another issue perhaps: I hear a short (2-3 secs long) audio from internal speaker and then just a blank (white) screen, and that's it. No screen saver, no nothing.
    – Ali
    Jan 14, 2017 at 13:43

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .