Mac Firefox Install Problems

I recently set up an OS X machine, installing 10.3 to start with (base install plus BSD subsystem), and then upgrading to 10.3.7 and installing the required security updates. Having a completely clean system, I decided to install Firefox. I tried to do the install from an end user perspective, seeing what kind of experience they could expect. I figured I was in a position to do this, since I know little about OS X. Here is that tale:

I fired up Safari (great browser, clean interface) and head over to to download Firefox 1.0. In true end user style, I decided to forgo reading any documentation whatsoever and just hit the large “Free Download” link.

A few minutes later, I had a Firefox 1.0.dmg.gz file on my desktop, which I double clicked on. I was greeted with the following dialog:

There is no default application specified to open the document Firefox 1.0.dmg.gz. [Cancel] [Choose Application...]

I chose the ‘Choose Application…’ option and tried to find something that could reasonably be expected to open .gz files, but I wasn’t able to find anything that matched that description.

Having now reached the point at which most end users give up, I decided to be a more savvy end user, and go and read up on some docs. So, off I go and I end up at the Firefox 1.0 release notes, which have install instructions:

Double click the Firefox Disk Image to uncompress and mount it. Your browser may have already done this for you. Double click the Firefox Disk Image to open it in Finder and drag the Firefox application onto your hard disk. Do not double click the icon in the disk image! Be sure to drag the Firefox application out of the disk image and onto your Hard Disk before running it. Drag the icon to your Dock if you want it to appear there.

Wait a second, didn’t I just do this? Safari had no earthly idea what to do with the .dmg.gz, so it didn’t open it, and obviously MacOS X had no idea either. Dead end.

The Camino download page had some instructions that looked potentially useful:

Once you’ve downloaded the .dmg.gz file, drag it onto Stuffit Expander to decompress it. If the disk image doesn’t mount automatically, double-click on the .dmg file to mount it. If that fails, and the file does not look like a disk image file, do a “Show Info” on the file, and, in the “Open with application” category, choose Disk Copy. In Mac OS 10.2, you can use “Open with” from the context menu.

But, my install of OS X didn’t have Stuffit Expander, nor did it have the Disk Copy application. After a little further research, I found out that starting in OS X 10.3, the functionality of Disk Copy was integrated into Disk Utility, but I was unable to get Disk Utility to do anything useful with the .dmg.gz file. Another dead end. This is way more than the amount of work we can expect 99% of end users to do, and I still hadn’t got Firefox installed.

Now, I realise that OS X has a BSD base, and has command line utilities to un-gzip files. But really, do we expect an end user to have to do that? I hope not. This install routine assumes too much about users’ systems and the tools they have at their disposal. This is not good.

There is an easy solution, which is to make Firefox available as a .dmg file rather than a .dmg.gz. We should be doing this anyway, because the standard way of distributing Mac software is via .dmg files. Presenting the user with a familiar install process will result in a much better user experience, with more completed installs. It’s rather unreasonable to expect end users to have to troubleshoot getting the installer disk image mounted.

UPDATE: The relevant bugs are as follows:

  • Bug 169602: [Camino] Use compressed disk image instead of gzip’d dmg for installer
  • Bug 242845: Firefox disk image should use .dmg internal zlib-compression, not .dmg.gz
  • Bug 268074: [Suite] Mozilla DMGs are redundantly compressed with gzip
  • Bug 276571: Thunderbird disk image should use .dmg internal zlib-compression, not .dmg.gz

UPDATE 2: Firefox, Thunderbird and Mozilla are all now distributed in compressed DMG format!

UPDATE 3 (11 May 2005): Camino nightlies are now distributed in compressed DMG format! Also, Mac OS X 10.4 (Tiger) no longer ships with Stuffit Expander installed by default, thus making this change even more important.

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22 Responses to Mac Firefox Install Problems

  1. Zach Lipton says:

    We probably should package as .dmg although that does increase download size. IIRC, the Disk Image format does provide for compressed disk imagaes already, I’ll look at the details later.

    To solve your particular problem however, Stuffit Expander comes with every mac. Macintosh HD:Applications:Utilities:Stuffit Expander. Should end-users need to know this in other to install Firefox? Absolutely not and we should fix that. On the other hand, it’s good to know where Expander is installed, as it’s a very handy tool to use in OS X for decompression; it will handle just about any file format and there’s no need to resort to the command-line.

  2. Zach Lipton says:

    Secondly, and perhaps more importantly: instead of including dire warnings about the need to copy Firefox to disk instead of running it from the disk image, why don’t we just make it possible to run from the image? Just make sure the image is a read/writable image and include a custom background image with some text asking users to copy the application to their Applications folder to install. This is how most OS X apps work.

    Oftentimes when testing new apps on OS X, I’ll run it from the disk image first to try it out. If I like it, then into my apps folder it goes. Otherwise, one command-delete and it’s gone for good…

  3. Ali Ebrahim says:

    Hi Zach,

    I checked in Macintosh HD:Applications:Utilities (again) for Stuffit Expander and couldn’t find it. It must have been one of the ‘Extra’ components that I deselected during OS X install (I installed the minimal required set of files, plus the BSD subsystem). Installing Firefox should really not depend on components that may or may not be present on any given system.


  4. Endorphinity says:

    Hi Ali,

    I am using FireFox since v.0.7 and was always wondering why it is not distributed as a compressed (sic!) .dmg file. Thanks for pointing at this at least now 😉

  5. Hi Ali,

    I agree that Firefox should be distributed as a DMG file. I’m not quite sure, though, which version of OS X first supported (internally) compressed DMG files.

    However, I think your “end user” approach is flawed. You apparently did a custom install of Mac OS X, instead of a standard install, as I would expect a true end user to do (who wouldn’t install the OS by himself in most cases anyway, I guess, since a Mac is ready to go when you buy it). I’d be very surprised if the standard install didn’t include StuffIt Expander.


  6. Ali Ebrahim says:


    As for my approach, you’re probably right that most end users will have Stuffit Expander installed, and I think the standard OS X install does it fact include it. However, I still feel that a better alternative is to distribute using an all-inclusive method, rather than one which is only semi-inclusive. Serving a plain .dmg doesn’t break anything for anyone, and is the standard method of distribution for software on OS X. If OS X has an established standard for software distribution, why are we deviating from it?

    Compressed .dmg is even better, but as you said, if it’s not be supported by the entire target audience, it’s probably not something that we can roll out yet (unless we offer both compressed and uncompressed, which will probably confuse end users).

    Still, none of this addresses this specific situation. How is someone in my postion supposed to proceed? Are they supposed to Google for an answer, know that they need to install Stuffit Expander, or just know that they can open Terminal and use gunzip?

  7. Hanspeter says:

    This would be Bug 268074. That’s filed against Seamonkey, but should really be applicable to FF/TB/SB as well. If I remember correctly. 10.2 definitely could handle internally compressed dmg files, and even 10.1 might have been able to deal with them.

  8. Arthur says:

    I distribute my Mac OS X software as compressed .dmg files and have had no complaints about people not being able to open them.

    And I have found that if you compress a compressed .dmg file it is in fact bigger than if you don’t. So the disk image compression is really great and the file will not be larger than usual.

    And I also think that the Firefox disk image should have a background image telling the user to drag the Firefox icon into Applications.
    Unless you make an installer package instead.

  9. Matt Brubeck says:

    Just today I downloaded Firefox on a brand new Mac, with no custom software installed or loaded. I downloaded it with Safari, and the image was uncompressed and mounted completely automatically.

    Normal end users will not remove programs like Stuffit from their installations. Advanced users who choose to omit utilities from the standard installation should expect to have to find some of those utilities later. (Lots of older Mac software is still distributed in Stuffit archives, for example.)

  10. From the manpage of hdiutil on Mac OS X 10.3.7 (emphasis mine):

    “Sparse images, encrypted images, and zlib-compressed images all did not exist in OS X 10.0.x but came into being with 10.1. These images will not attach (or will attach read/write allowing for their destruction) on OS X 10.0.x.”

    System requirements for Firefox include Mac OS X 10.1 and up, so it would be OK to distribute internally compressed DMG files–and definitely preferable.

    I agree that it would have been very helpful in your situation if the docs said something about needing StuffIt Expander, and where to get it. However, it is a standard piece of Mac software, and has been for years, maybe even for decades. So I think it’s understandable that it hasn’t been mentioned explicitly. It’s one of those too-obvious-to-see things.


  11. steeef says:

    I don’t think it’s that unreasonable to download a gzipped dmg. Just downloading a disk image would be like asking Windows users to download an uncompressed folder to install Firefox. It’s unnecessarily large.

    Like Zach said, StuffIt Expander comes with OS X, and provided you do the default install, Safari has no problem running it when you download any gzipped file.

    I don’t think the fact that you happened to not install an ubiquitous utility warrants changing things for everyone.

  12. Hanspeter says:

    steeef: these wouldn’t be uncompressed disk images the size of the fully installed package. They would be internally gzipped (rather than gzipped after the fact like they are now), so the final size would be pretty much the same as they are now (maybe a few kb difference). The main benefit would be that only Disk Utility has to launch, rather than first launching StuffIt and then Disk Utility later. And it would also eliminate the intermediate (large uncompressed) file that is left behind by StuffIt.

  13. Obviously, the right way to go is using the internal compression of disk images. However, not installing StuffIt Expander is extremely impractical. I can’t imagine anyone but an experienced computer user with no Mac experience to uncheck it. People without a lot of computer experience go with the default install and people with previous Mac experience are likely to want StuffIt Expander.

  14. Ali Ebrahim says:

    If compressed .dmg is supported starting in OS X 10.1 onwards, then there’s no reason why we shouldn’t be using it, since we don’t support OS X 10.0 anyway. It would provide users with a much better user experience.

    I now realise that not installing Stuffit Expander was probably impractical. But hey, I’m a newbie with OS X. I wonder how many other newbie OS X users who tried to be too smart made the same mistake as I did?

  15. Ali Ebrahim says:

    Hi Arthur,

    Thanks, but I’ve already updated my post body with the links to the relevant bugs for Firefox, Thunderbird, Camino and the Suite. Check it out at the bottom after the word ‘UPDATE’.

  16. someone says:

    Since OS X 10.1, stuffit was always included with the default install hence the end user would not have any problem double clicking on the tgz/gz files for it to uncompress. Now for advanced application selection installs, you should have selected for it to install the utility.

  17. anonymous says:

    Actually basic stuffit expander has ALWAYS come with Mac OS not only OS X.

    Ali seems to be installing a custom version or something, other then that all my disks that I buy from apple of OS X (trust me we buy many) all come with stuffit expander when you default install from cd.

  18. imran says:

    on my newly installed os x 10.3 as soon as I clicked on the tgz/gz file, stuffit launched, unpacked and quit leaving me with a dmg.

  19. Ali Ebrahim says:

    Camino nightlies are now distributed in compressed DMG format! Also, Mac OS X 10.4 (Tiger) no longer ships with Stuffit Expander installed by default, thus making this change even more important.

  20. Janet says:

    Help, I am a newbie!
    I have a eMac 1 GHz G4 256mb version 10.3

    Need to install Firefox to play a video clip.
    This is the warning message I get

    Firefox 1.0.4.dmg no mountable file systems

    What does this mean and what’s missing. I have just installed windows media.

    Any advice welcome.

  21. Ali Ebrahim says:

    Janet, try asking for help on — I’m not sure what this error means.

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