Happy Birthday, Mac - How to Recover From the Dreaded Bomb Box Error Message

| How-To

Thirty years ago to this day, the Macintosh became available to the masses. What exciting times those were. I plunked down my $2500 for my Macintosh 128K plus $50 for a box of 10 Apple-branded single-sided floppy disks. That was the beginning of my thirty-year love affair with Mac computing – warts and all. 

In fact, the Mac’s existence defined my 20+ years IT career, as I became the lead Mac support specialist and trainer for a major Delaware-based chemical research company. I’ve written many a How-To article since those pioneer days.

In homage to the 30th Anniversary of Macintosh, I present you with a How-To article from the late 80’s; one of many I wrote for the Mac-toting scientists and support staff at my Company’s research center. Any old-timers should relish reliving the past for a moment. Most of my readers here on TMO were probably either non-existent in those days or too young to recall any of this. If you fall into this category, read on, and get a taste of what we had to put up with before OS X, before Mac OS 9, Mac OS 8, and even before Mac System 7. Enjoy.

How to Recover From the Dreaded Bomb Box Error Message

As Macintosh users we've come to expect the dreaded bomb box error message from time to time, haven’t we? Actually, not a day goes by that we’re not blasted by the baleful bomb. If not the bomb, we experience what's known as a “system hang.” That latter ominous-sounding event occurs when the Macintosh simply decides to ignore your mouse and keyboard and is rendered totally unresponsive.

The old Mac System Bomb dialog box

A day or two don’t go by that we don’t get this happy news on our Macintosh screens

Whether it’s a bomb or a hang, I’m afraid that our options are highly limited. What can we do?

If we see the bomb box on our Macintosh screen, the easiest thing to try is to click on the restart button that accompanies the bomb. In reality, it's more likely that the bomb is so insidious that the restart button won't respond. Yes, not only did the Macintosh bomb, it hung, too!

Here’s something else to try: you could press the reset button on the Programmer’s Switch.

The Programmer’s Switch

The Programmer’s Switch comes with every Macintosh, but you have to install it properly in order to use it.

What is a Programmer’s Switch, you ask? You know, the odd but official-looking little piece plastic that came with your Macintosh 128K, 512e or Plus. The one you didn’t know what its purpose was. That thingamabob that hardly anyone knows what to do with. Did you insert it in it’s elusive slot on the left-rear side of your little one-eyed buddy?

In any event, your only other recourse for getting things back to normal is flipping the Macintosh's power switch off and then back on, waiting for that comforting startup bong. 

The problem with taking any of the actions mentioned above is that all the information that you had not yet saved to your disk ends up in the bit bucket; forever lost. If, unlike most of us, you’re lucky enough to be using one of those newfangled, state-of-the-art 10 MB hard disk drives, you will have to wait five to ten minutes while the hard disk utility software checks to make sure everything is okay before starting up your Macintosh.

The original box of Apple floppy disks for the Mac

Ten Apple-branded, single-sided diskettes will set you back $50

This is why it is so important to get into the habit of issuing a manual Save command every couple of minutes or so while working on your document. This is easiest done by pressing Command-S  – the keyboard shortcut for the Save File command. I hope I’m still around when the day comes that our Macintosh will be able to save our documents automatically! Then again, that day may never come.

Back to the problem at hand. There is a special secret technique that my Macintosh support colleagues and I will try first in order to avoid losing data. Not to be too pessimistic, but this rarely works, often simply giving us a second bomb box followed by a system hang. But hey, it’s worth a try on the slim chance that you can recover any unsaved data. It’s important to note that this technique is possible only if you're Macintosh has both the 128K ROM (Read-Only Memory) and the Programmer’s Switch installed.

A detail of the Mac Plus logic board

The Macintosh 128K logic board is a thing of beauty

As you know  – if you actually have it installed  – the Programmer’s Switch consists of two buttons: the Reset Button is the forward one, and the Interrupt Button is behind. When you press the Interrupt Button a blank text-entry box appears. This is like a terminal window or command-line interface area for the internal debugger that comes with the 128K ROM. It’s a utility made available for Macintosh software developers to use for troubleshooting.

Type in the following cryptic text, pressing return at the end of each line. Be sure to type the letters in lower case as shown, even though they will show up as upper case in the box.

The Macintosh Debugger command window

Type these characters as shown to attempt avoid losing data when that bomb appears

Good luck with that. In reality, it's highly likely that this technique will not work at all. In fact, there is a chance that this technique will damage the files still in memory, although I personally have never experienced anything like this. Come to think of it, I can't recall a single instance when this technique worked for me or my colleagues at all!

Software titles that are incompatible with the 128K ROM

When you upgrade your Macintosh to the 128K ROM and begin to take advantage of HFS (the new Hierarchical File System used by the Finder), be aware that early versions of the applications listed below are not compatible. Be sure to contact the software publishers to request replacement floppies containing the latest version of their software. You can find their telephone numbers printed in the software manuals that came in the box with your program floppies.

  • ConcertWare +
  • ClickOn Worksheet
  • Dollars and Sense
  • Hayden:Speller
  • MockWrite
  • MusicWorks
  • Red Ryder
  • Sargon III
  • SIdeKick
  • Note-pad+
  • Smartcom II
  • ThinkTank
  • TurboCharger

Finally, Apple advises users of machines with just 128K of RAM (Random Access Memory) to stick with System version 2.0 and Finder version 4.1. System version 3.2 and Finder version 5.3 (or later) are only designed for systems with the 128K ROM installed.

Oh, and don’t forget to read your Mac’s owner’s manual!

The Macintosh Plus owners manual

Your Macintosh Owners Manual should be a permanent fixture on your computer desk

There you have it!

Now, how many of you old-timers out there remember those exciting Days of the Bombs? I wonder who remembers those gems from the above list of programs – from back in the day before applications were called “apps,” and when the Macintosh smiled back at you every time you turned it on.

The original Smiling Mac icon

Once the Mac finished it’s startup diagnostics, you were greeted with a smile indicating an A-OK condition

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Ah yes the Bomb Box and Programmers Switch. That brought back memories. Loved the comment about auto save and how that day may never come.  Never understood why the programmers switch wasn’t installed at the factory though.



Got started with the Mac in 1988, renting time on Mac Pluses at Kinko Copies and doing extremely rudimentary DTP that seemed at the time borderline magic. This article brought back many memories, including the programmer’s switch I’d completely forgotten about. @geoduck, I’m guessing they weren’t pre-installed because they weren’t as user-friendly as the rest of the machine. Kind of like “expert mode” or “developer mode/menu” in some apps today.


I go back to the end of 1985 (I believe) when I bought my first Mac which was a Plus at a store in Salem, NH. The salesman talked me into the $2499.00 purchase over the many generic PC computers in the store. I heard a new word that day which convinced me: WYSIWYG. I still have that Mac and it still runs like a charm slowly.

All the things you mentioned bring back memories. Bombs, programmer’s switch and the constant need to remember to save. Really, it was more likely that I would be kicking myself for forgetting to save. But the real nostalgia for me is remembering System 7. What an advance in power and usability it brought.

One other thing about remembering the Mac’s past is the cost. Now that is something which I am glad has gone way down.


My wife’s company was a all Mac Plus. Internal email, billing (Filemaker), all done on a series of them. They did all their art paste-up, and when they did go digital, their systems guy got them on Windows for art. What a mess. However, it did get my wife into digital prepress which is when we got our first home Mac - a Performa 450. (The pizza box Mac). I remember upgrading to 12MB RAM - that 8 MB chip cost us nearly $300. Later we upgraded the VRAM for a little under $100. It took so much time to install software with floppies that I used to copy the floppies into a file folder and install from there. Way quicker. Ah, the good old days!

I have a 512 (operable last time I checked) that we got when her next company retired one. Yes, it has the signatures inside the case.


What a great piece!

I didn’t come on board until System 7, but I saw a bomb or two in my day, they had a lot more character than our modern kernal panics. wink

Ah, those were the days. smile

Steve Aldrich

I remember the bomb box and the Interrupt Switch. Got to see (and own) a lot of the early history of Apple computers due to working in a store that bought and sold computers in Ann Arbor, Michigan - once known as having the largest population of Macintosh computers outside of Cupertino. At one time, I owned a 128K & a 512K Fat Mac, a Lisa 2, an XL and a Woz-autographed Apple IIGS. Still have the IIGS; wish I still had the others.
I also remember a bit of prank software you could install on someone’s Mac where an inviting-looking icon of a woman’s head would bring up the bomb box, but whenever they tried to point to the Restart button - it would move! I believe it was included in “Stupid Mac Tricks” by Bob Levitus.. Had a lot of fun with that and others like it.


Thank you Susan Kare!
xo xo


I’ve still got a couple of the Programmer Switches.


Same here, I still have several programmers switches - installed on systems that I’ve collected overs e last 20 years.

I didn’t start using Mac’s until System 7, but I definitely invoked the programmers “switch” on my IIsi a time or two to try and recovers from hangs.

This brings back good ( and not so good ) memories. That’s for the flashback article Sandro!




Nice! Both styles smile

I just just did a quick count and I have one of the newer style on my SE/30, and three of the older style on my 128k (upgraded to 512k), 512k, and 512ke.

Newer models like the Classic and Classic II had buttons that were built-in.


Loving the trip down memory lane, scary thing is that it doesn’t seem that long ago at all. Booting from a floppy then regularly having to reinsert the system disk was an eternal annoyance. I never used to know what to do with the blank interrupt box - wish I’d known to try this before, but it was well before the internet and helpful web sites. *sigh*

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