On my iMac, I keep a lot of supervision windows (displaying alarms and trends). These windows lead to priviledged access to very sensitive equipments. I would like to protect this iMac from any accidental typing on the keyboard or mouse mouve, and password protect it from any other local access.

I would like to be able to start my screen saver (which will lock my mouse and keyboard by asking my password), but to keep a full acces to the actual display.

Is there any way to make a transparent locked screen?

3 Answers 3


Update: Transparent 2.4 works for external displays.

I have this question and tried the other answers.

The JohnnyNash and Transparent screen savers both work .. almost. They show the main screen, but external displays go black. The difference between these savers is that JohnnyNash is configured to update in seconds, and Transparent is configured to update in frames-per-second.

The Black Light screensaver boasts many features, but I did not see transparency on the list.

I found a screen saver called LookThrough, which boasts multi-monitor support. It sort of works in that it displays on all of my displays, but the graphics are glitched up in weird ways.


The JohnnyNash Transparent screensaver works (weeks of testing in production environment) correctly on:

  • Lion
  • Mountain Lion

The internal description of its functioning does exhibit a pretty good level of transparency. Read full and simple documentation here: JohnnyNash - Screen Saver

To install it, just open the disk image, and johnnynash.saver.


While I did not install any, there seem to be some "transparent" screensavers available for download. A transparent screensaver would accomplish what you are trying to do.

Have a look at, and try:

  • My tests on Mountain Lion failed. Thank you for your attempt to help :).
    – dan
    Commented May 10, 2013 at 8:51

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