Why is there a screen that says “It is now safe to turn off your computer”?

I don't know whose idea it was, but Windows 95 added a screen that appeared when you shut down Windows.

It's now safe to turn off
your computer.

This message was added because people would shut down Windows and then not know what to do next.

I witnessed this first hand once.

I was on an airplane flight, and the person sitting next to me was trying to turn off a laptop computer, which was running Windows NT. After selecting "Shut down", the operating system shut itself down, and then it displayed a screen that looked like this:

🌙  Windows has been shut down.

My seatmate saw this screen and clicked the Restart button.

Of course, this restarted the computer, and Windows started up again.

My seatmate, somewhat confused as to why the computer didn't shut down, selected "Shut down" a second time.

Again, the screen appeared:

🌙  Windows has been shut down.

And my seatmate performed the only option available: Restart.

At this point, I took the liberty of informing my seatmate, "You can just turn it off when you get to the moon-and-stars dialog."

"No, I can't do that. I was told I have to use the Shut Down menu to shut down. But the computer won't shut down!"

I had to explain, "This particular laptop doesn't know how to turn itself off. You have to turn it off manually via the power switch. Just wait for the moon-and-stars dialog to appear, and then you can push the power switch."

I'm guessing that the person on the plane next to me normally used a laptop that supported power management, and it was able to turn itself off via software. But the laptop that was brought onto the plane did not support power management, and it had to be turned off manually. And back in the day, most computers fell into the second category. Power management was one of those newfangled thingies that only the fancy-pants computers supported.

Enter the It's now safe to turn off your computer screen.

This message was displayed when shutdown was complete and the computer did not support software-initiated power-off. It told the user, "Okay, shutdown is complete. It's okay. You can hit the power button now. I won't get mad; I promise."

Comments (60)
  1. JB says:

    It was wrong anyway. If I’m using someone elses computer and shut it down and it tells me “It’s now safe to turn off your computer” I have to go back to my own computer and power it off because THIS ISN’T *MY* computer.

    1. Did you have the same reaction to the My Computer icon? Perhaps you should not use computers that don’t belong to you in that case.

      1. Matthew says:

        I don’t use My Documents because there’s nothing in there that I actually created.

      2. Karellen says:

        I had that reaction to “My Documents” and all those similarly-named folders. If there’s a folder called “My Documents” and I didn’t create it, it must not be mine, it must be someone elses. So I’m not going to store my documents there, or even look in there, because it’s not mine, and I don’t want to pollute someone else’s set of files.

        I know I didn’t create “My Documents”, partly becuase I don’t remember creating it, but also because I wouldn’t name it “My Documents” if I had. So I always ended up creating my own folders for storing things in, and being annoyed whenever I wanted to load or save a file at having to navigate out of the folder called “My Documents” to the folder containing my documents.

        1. exchange development blog team says:

          I got annoyed at the cutesy names as well, which was why, for a long time, my PC had “Ma Bitch” and “Da Hood” instead of “My Computer” and “Network Neighbourhood”.

        2. smf says:

          In England we have a saying that covers this situation “cutting off your nose to spite your face”.

  2. pc says:

    Even though Raymond’s mockup here isn’t a real image, if my memory serves me the real screen was an actual bitmap file (maybe embedded into one of the Windows executables?). I’m curious as to why it was a bitmap to just display a couple lines of text. Was it originally going to be more graphical (with it own moon and stars, say), or did it make it easier to localize, or was it actually easier as the last-step-of-unloading-everything to render a bitmap to the screen than to draw text?

    1. dirk gently says:

      I remember I replaced the bitmap with one that said “I’m an incredibly stupid computer, please end my misery” or something to that effect.

    2. Euro Micelli says:

      Assuming you recall correctly, it’s probably just that “Windows has shutdown”. There are no longer any font rendering facilities available, or little else for that matter. You just have some (possibly real-mode, probably assembler) code that knows how to switch a VGA card to a specific graphics mode via BIOS, and how to dump a pre-rendered graphic buffer to video memory. The only other thing you could do was to switch to text mode and print a text message, but that would have been “uncouth”.

      Granted, they could have rendered the graphic from text on the fly, right before the shutting down.

      Maybe they wanted to assume the bare minimum was operational during a shutdown in case of a controlled crash?

      Or maybe be the original concept was to have a fancy graphic with a nice background, and only later did they decide a simple phrase in a muted color was the best way to convey “I’m done”.

    3. Medinoc says:

      My guess is simply that it allowed them to re-use the code that displayed the cloudy image “please wait while your computer shuts down” during the shutdown process.

    4. Antonio Rodríguez says:

      In Windows 95 (and 98 and Me), the message was shown after the VMM was shut down, so the system was effectively in DOS mode, so there was no GDI or graphics drivers to display anything fancy. IIRC, the message itself was displayed in a standard (but undocumented) VGA video mode: 320×400 at 256 colors, the same one used during the boot splash/animation.

      Displaying a bitmap at that mode is simple even without any video driver: just fiddle with a dozen VGA registers to set up the video mode, load the bitmap from disk issuing an int 21h call, and copy it into the video RAM. In fact, it was slightly more complicated: 320×400 needs 125 KB of VRAM (128,000 bytes), and the VGA standard only allowed paged access to the VRAM though a 64 KB address space window, so you had to copy the bitmap’s first half, switch the page, and then copy the second half. But you get the idea.

      To display a proper text, you would have to load a graphics library, a font and possibly a video driver. A lot more work, especially for DOS mode (and its 640 KB limit). Way too much for a static message.

      When I switched back from Windows 95 to MS-DOS 6.22 and Windows 3.11 (with Calmira Explorer!), I created an “apagar” (“shut down” in Spanish) command which disabled SmartDrive’s write cache and then displayed a bitmap. I used the image from Windows 95, but scaled down to the documented 320×200 because I didn’t bother to support in the viewer the paging needed for the 320×400 mode :-P .

      1. Yuhong Bao says:

        It is not actually SVGA-style bank switching, as the VGA hardware did not work that way.

    5. Joshua says:

      The Win9x one was indeed a bitmap and you could indeed replace it.

      The NT one was text and icon. The icon appeared as winlogon’s icon up through XP.

      1. Sockatume says:

        I remember a lot of ’90s game installers would let you replace the normal “safe to turn off your computer…” screen with something appropriate to the game’s fiction, to go with the special sounds and desktop icons that also came with the game. And some people just edited it for a laugh. Computers you had to turn off manually seemed to be the norm for quite a while, at least in my neck of the woods.

        1. RP says:

          They were indeed the norm. Raymond already said so (“Power management was one of those newfangled thingies that only the fancy-pants computers supported. “).

          I remember being a little surprised the first time a machine turned itself off after shutdown.

      2. I just checked in my virtual Windows 95 machine and the startup, shutdown and post-shutdown bitmaps were found in C:\logo.sys, C:\WINDOWS\logow.sys, and C:\WINDOWS\logos.sys, respectively. These can be opened in Paint. I haven’t checked, but probably they are normal BMP images with a different file extension.

        1. Erik F says:

          Indeed they are standard BMP images, but the startup graphic uses palette animation and has to be set up in a specific way (http://www.xrx.ca/logoutils/win95logo.htm). It’s a shame that palette animation is basically dead nowadays, because it seems like a great way of animating things without a lot of changes, but I realize that palettes in 24-bit colour spaces don’t really make much sense.

          1. Sure palettes in 24-bit RGB mode “make sense” – you can still create a palette, load it using SetPaletteEntries and select your drawing (or whatever) color with the little-used PALETTEINDEX macro. It’s a convenient way of creating and choosing from a limited set of predefined RGB colors. But of course you cannot ‘animate’ the palette in that case.

        2. Fernando says:

          Yes, those are standard BMP renamed with the .sys extention. The logow.sys means “logo-wait” and “logos.sys” means logo-safe. You can get really creative with logo.sys palette animation feature, even do some small frame-by-frame animation that looks really nice. A long time ago i took an animated gif of a rotating skull and convert-it to be shown in the boot screen.

    6. Wayne says:

      At this point Windows 95 had actually dropped down to DOS. So while it’s displaying the bitmap in graphics mode, there’s a DOS prompt there you could actually type into. If you typed the appropriate command you could reset the video mode and continue working in DOS.

      1. Karellen says:

        mode co80

        …if I remember correctly.

        1. Fernando says:

          Almost, was “mode con 80” to switch to text mode with 80 columns-

        2. cheong00 says:

          I think had Windows just switch back to DOS prompt when “Shutdown” is selected and there’s no shutdown facilities (in case of Win98), there will be little confusion.

          People who are used to Win3.X will instinctively know to power off the machine when they see the DOS prompt.

        3. Drak says:

          mode co80.. that brings back memories :D

        4. RP says:

          That’s what I heard, although it never worked for me. Perhaps it got removed in OSR2 or something?

  3. Stephan Sokolow says:

    The Windows 95 solution is a perfect example of design well done. A simple solution that’s “obvious” in hindsight, but, if you can manage to put yourself into the mind of someone who didn’t already know, it’s surprisingly non-obvious.

    (The same principle also defines good writing in fiction. A mystery before you read it, blindingly obvious in hindsight.)

  4. I wonder: Does any current Windows version support a ‘computer has been shutdown’ screen? If not, when did support stop?

    1. It stopped when Windows required ACPI, which appears to be Windows XP (documentation seems a little sketchy here). Windows 2000 supported APM but had to handle dealing with computers using problematic APM BIOSes, so it still would’ve needed the shutdown screen. Windows 9x supported APM and ACPI, but didn’t strictly require either one (because APM was buggy and ACPI was too new), so all of its versions supported the shutdown screen.

      1. Joshua says:

        Uhh said Pentium I had ACPI but not power knockout, and I’ve got a picture somewhere of XP’s “It’s now safe to turn off your computer.” screen.

        1. Josh B says:

          Yup, XP “required” ACPI, but would still install without it. There were also a handful of popular drivers (ZoneAlarm, Logitech, Adaptec DirectCD) that would break it.

      2. Antonio Rodríguez says:

        The “It’s now safe to turn off your computer” message was shown in a friend’s AMD K6-based PC with Windows 2000. Later he upgraded it to Windows XP, and I believe it showed the shut down message too, but I’m not sure.

        1. ender says:

          XP had this screen:

          (reproduced in PCem with XP installed on an emulated Pentium Overdrive CPU)

      3. Yuhong Bao says:

        XP/Server 2003 was the last version of Windows that had the non-ACPI HALs.

  5. BZ says:

    Ultimately it’s a chicken and egg issue. The users would have only been trained not to ever touch the power button if power management became widespread, by which point it didn’t matter what was displayed because it would have been unexpected. On the other hand, Windows 95 users would presumably be coming from Windows 3.1 where they would be waiting for a DOS prompt to hit the power button, so any type of message would be new. I suppose the one that was chosen was the obvious choice, except for those using Windows NT at work (did anyone ever complain about the restart button not being provided?)

    Anyway, I definitely recall seeing the NT message or something similar to it, though the first version of NT I used was NT4 in a college PC lab where you couldn’t shut anything down. I did run Windows 2000 on my own PC since late beta, though the computer was from 1998 and would have shut down automatically (I think). So, if it survived to 2000 beta and ACPI wasn’t properly detected or something, I would have seen it there.

    Maybe it was a copycat in a different OS? I don’t recall anything other than “System Halted” in Linux

  6. Boris says:

    But if this was a problem, why not be even more specific and say “It is now safe to press the power button”?

    1. Sockatume says:

      Some computers had switches.

      1. Antonio Rodríguez says:

        In fact, most computers without software power control *had* switches. The power button changed from a passive on-off switch to a push button when ATX motherboards and power supplies became mainstream around 1998 or so. So, AT=power switch=no software control, ATX=power button=software control. And in those days, it could happen that an ATX system without the proper ACPI drivers had a push button but displayed the shutdown message.

        1. It’s not quite that simple.

          I’ve got an AST Adventure! 210 (P1 133MHz) sitting on my nostalgia gaming desk, running one of my old copies of Windows 98 SE, and it doesn’t have software power control but the “switch” is one of those physically-latching press-in/press-out pushbuttons.

          Until you actually press the button and feel the increased weight and latching effect (and hear the more solid clicking sound), you’d mistake it for an early ATX machine.

          I used to have a 33MHz 486 which looked similar but went even more primitive and connected the front pushbutton to the rear-mounted PSU via a polycarbonate rod along the inside of the right edge of the case rather than a wire.

    2. BZ says:

      Maybe people didn’t know it was called the “power” button? It doesn’t necessarily say “power” on it

    3. Kevin says:

      Maybe it wasn’t a button. The last PC I owned without ACPI shutdown support had a physical toggle switch. The last PC I remember seeing this on had a broken ACPI implementation and you had to hold down the power button for X seconds.

    4. Nathaniel says:

      Some computers of this vintage had power switches rather than buttons as well. I don’t think that it’d be safe at all to assume what action would cause the computer to turn off.

      1. Not to mention in certain industrial deployments or cart deployments, the computer would be wired to a power strip or something similar and you’d have to flip the switch from there instead.

    5. Adam V says:

      > why not be even more specific and say “It is now safe to press the power button”?

      Because non-techies are going to turn off the *monitor* when they read that, then they’ll come in the next morning and turn it back on and wonder why it still says that.

    6. Boris says:

      Point taken, so how about “It is now safe to power off”? This should cover everything from flipping a switch to yanking out the power cable.

      1. Too vague. What is the user supposed to power off? The monitor? The computer? Does the user even know the difference? Might as well be explicit and say “power off the computer”, at which point you’re basically at the exact same message that Microsoft used.

  7. Relevant YouTube video: http://www.youtube.com/watch?v=8ucCxtgN6sc
    Jump to 7:25 if you want to see the shutdown process.

  8. Ilhan says:

    Do we have such message in Windows 10?

    1. Joshua says:

      You know, I’ve been curious to find out but my last machine that can’t power off on its own was a Pentium I. I don’t have to elaborate on why that can’t run Windows 10 and I’m not silly enough to try to request it of MS.

    2. No; Windows has required ACPI support since Windows Vista. If the BIOS/UEFI chip doesn’t implement ACPI, it won’t allow you to install on the computer since it has no HAL to deploy. If your BIOS has a buggy ACPI implementation, then Windows will show a BSoD complaining that ACPI went out of sync. You can boot with a disabled ACPI driver, however; if I were to guess, this probably causes Windows to fall back to APM, which supports restart, standby, and shutdown, but not hibernate. Not sure what happens if it doesn’t even have APM to fall back to, probably another BSoD.

      1. Yuhong Bao says:

        I don’t think Vista even has the APM code. Even the support in 2000/XP for it was limited.

        1. I wonder what Windows does then if the ACPI driver is disabled. It can still boot, so maybe it still initializes ACPI but doesn’t do the advanced power state management that ACPI allows for?

  9. Stuart Trusty says:

    This screen, and OS, was for people like my customer of Computerland in ’88, a farmer in Washington State who had bought a PC XT, a printer, and a suite of expensive accounting software. He came back in a week, complaining… “I set up this system and it seems to be running fine, but it hasn’t produced a single report!”

  10. Shawn says:

    I remember how facinated I was when the Windows NT OS made boot-up, shut-down, and even the “safe to turn off” screens all look like a dialog rendered by the operating system. I was pretty young but I remember wondering where DOS was.

  11. ZLB says:

    Oh this post brings back memories!

    In the theme of ‘Pranks that didn’t go well’, a teenage me thought it would be hilarious to write a screensaver that just showed the “It is now safe to turn off your computer” screen and I covertly installed it on some friends, family and school computers.

    Very funny! Leave your computer for 5 minutes and it’s shut itself down. Much stifled laughter. Much unsaved work lost.

    Kids are horrible!

  12. DWalker says:

    I have helped people with computer training, and they ask “what do I do now” after we are done with a program and we close that program. Or after we shut down the computer.

    The answer, I suppose, is “go get a pizza” or “have some coffee and pie”. I don’t know what you want to do now; go for a walk; feed the kids; etc. We can’t plan your whole life!

    1. Boris says:

      I can think of many useful topics:

      1) How to clean the keyboard, screen, and mouse
      2) How to remove dust from inside the machine
      3) How to upgrade RAM, install the fancy CD-ROM drive, maybe even a network card

  13. John Payne says:

    This used to make a great screensaver! Remember that joke? ;)

  14. jgh says:

    Argh! Yes Yes Yes! I witnessed this so many times. To solve a similar problem, I edited the shutdown screen to say: “It is now safe to turn off your computer, or press ctrl-alt-del to restart” after watching far too many people turn the computer off and then on again in order to “escape” from the shutdown screen.

  15. Vince says:

    I seem to remember you could type CLS on the Win95 “It’s now safe to turn off your computer.” screen and get a DOS prompt…

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