Xslimmer at MacAppADay


If you’ve been following MacAppADay as I have, you’ve already seen that today’s freebie is Xslimmer. I had no idea this app existed previous to this (MAAD seems to be doing it’s job in that respect) or even what it did. Maybe I’m behind the times.

For those in the same boat as myself, it’ll only do you any good if you’re running an Intel-powered Mac. See what it does, is remove the none-Intel code from Universal applications, slimming them down and saving you space. Interesting idea.

My feelings on this are:

  1. How strapped for hard drive space must you be to feel the need to remove a couple megs of bloat from an applications?
  2. Should I fully trust this thing from not hosing one of my programs? (granted, it’s simple enough to re-download/install, but still)

I don’t know. I’ve got a couple trial apps on my system right now that I’ll probably try it on, and see how it goes. At the end of the day however, maybe I’ve freed-up 100 megabytes of space (and I think I’m being pretty liberal with that number) on my hard disk. Is that worth the $6.95 introductory offer they’re asking ($9.95 regularly)? While the price tag is low and reasonable, for me, I don’t think the utility I’d get out of it would be worth it.

If you’ve got experience with Xslimmer, I’d love to hear them. Do you think it’s worth $7 or $10? Do you see real merit in its slimming capabilities?



weldon — For most apps, that’s true. Some, though, tend to actually double in size from single-platform to Universal. I don’t remember which, but several of the apps I slimmed went down by 50 percent or so.

I think largely it depends on whether the app includes any dylibs, frameworks, extensions, etc., of its own (which would also be Universal and thus available for slimming).


I don’t think it’s worth it. The biggest part of an app bundle are all the resources like images, interface elements, sounds, etc. Trimming out the binary code is the smallest part of the app. You’ll do a lot better getting rid of themes in iLife and sample loops or instruments in Garage Band.


Don’t use Xslimmer on the beta release of Adium! It completely destroys it. I can’t even launch the app anymore! ARGH.

Vincent Tavera

I haven’t read all the comments, but the post I am commenting on said that xslimmer was for intel macs, but it works on ppc to remove intel portions of apps as well. :D


Nick and Grant — Glad that my comments helped persuade you to give XSlimmer a second chance. I’m not getting any kickbacks from them, but I like good apps that accomplish tasks simply and cleanly. This is one of them. For me as a former Unix admin and kernel programmer, the “safely” portion is just icing on the cake, but I can see how others would balk at scrambling the bits of their executables.


Thanks to all who chimed in. I will be busy slimming down all of my apps now if anyone needs me.

Nick Santilli

Billifer – Thank you for the detailed explanations. I must say I feel a lot better about giving the thing a fair shot after all that.

And I’m extremely impressed by the ‘nearly a gig’ of space freed-up. I wonder how that translates to a similar trial on an Intel machine…maybe I should find out.

Thanks again for the input

Derek Punsalan

I just wanted to chime in with my thoughts on the application. I think it’s a great utility for anyone running UB apps / utilities on their Macs. I feel comfortable dropping any apps into Xslimmer due to the fact that backups are created in the directory of my choosing. Great way to cut the fat out of UB apps when the extra archicture has no effect on your system performance.


Ben’s right: XSlimmer doesn’t help only those of you on newer MacBook (Pro) systems, but also those of us running on PowerBooks, iBooks, etc. We need Universal binaries even less than you do on Intel systems.

XSlimmer, by default, will not allow you to thin an application that exists in /System, /Library, or /Developer (even though some of these can be slimmed just fine). It also supports a blacklist of applications that cease to work correctly after they’ve been thinned — Linotype FontExplorer X, for example. Also, a preference can be set to backup all applications to another directory before thinning them.

Those three functions make XSlimmer a fair shot safer than using the Tiger-bundled command-line tool lipo to accomplish the same thing. [lipo, for instance, will allow you to overwrite a file, without making a backup first, even if it’s a single executable file (or dylib or what-have-you), not just an application bundle (*.app), which is all XSlimmer will allow in my experience of the application.]

I downloaded XSlimmer from MAAD last night, ran it through my entire Applications folder, most of my Developer folder (knowing what not to touch), and ended up saving close to a full gigabyte of space on my PowerBook G4. That’s substantially more than “a couple megs of bloat.”

Those who play things hypercautiously and don’t even like the idea of changing desktop backgrounds or from “Blue” to “Graphite” might want to avoid using XSlimmer, but for most users, XSlimmer takes sufficient safeguards to ensure that any mistakes can be corrected. Just be sure to run the thinned app to make sure it’s A-OK before deleting the backed-up copy.

Richard Neal

Given that’s it’s pretty easy to do this from the command line, and that there are free applications such as TrimTheFat that do as well, it’s definitely not worth much. I picked it up at MAAD as well, but it’ll probably just languish in a folder along with shadowClipboard and MailSteward until the end of time.

Nick Santilli

Alex – nice point about the Disk Image/install workflow. That’s kinda cool.

I guess I should mention too – it seems this app would go both ways – not just work for Intel based macs. As it would trim the intel stuff out if you’re on a G4 for instance. I don’t think I wrote it with that understanding up above.

Jason – yeah, support would get hairy. I’d think the only things people would really go for the support on, would be something like Photoshop when it finally goes Universal. And even then, I’d do a reinstall before calling for support. But I get your line of thinking.


this post is wrong: i’m using xslimmer on an ibook g4 and it takes out the intel data that i don’t need. it cut google earth’s size in half, and everything still works great. it’s a small app that does one thing well, and it even has a backup function if you’re worried about your apps.

Jason Alexander

Yeah, that just seems scary to me! Does anyone have any ideas what that does for your product support? ie, you slim your apps, then have a problem, call into the vendor and they say, “Sorry, you used slimmer which does things to our code that’s not really intended.”?

As an ISV, I know I would certainly void all warranties and support. And, with that being said, I’d say it’s certainly NOT worth the $7/$10 it costs, when it may potentially cost you MUCH more in the long run.

My .02 of course. :)


Similar to Adam, I was apprehensive about slimming my apps, but I figured “meh, I can just download them and install them again”, so I ran it.
It worked like a charm, and saved a couple hundred MB’s. I think what I actually like the most is you can drag an app from a disk image and it will install it and slim it automatically, making it easy to keep your apps lightweight.
Necessary? Probably not. Easy? Very.

Adam Spooner

I can’t remember where I first heard about Xslimmer, but I purchased it for $7 a while ago. I purchase indy apps (esp. inexpensive ones like this to support the community) on a regular basis.

I was scared to death when I decided to slim all of my apps (after testing it out on a few apps) for the obvious reason of something going heinously wrong. I tested it on my laptop (the last of the G4’s) and it worked like a charm – all apps are working like they’re supposed to. So I decided it would work fine on my main machine (new Core 2 Duo iMac)… and it did just that. All apps are working properly.

Is it worth $7/$10? I’m not sure, considering I saved only a few megs. I guess I just like to support independent developers. =)


i also grabbed this app in the GiftZot. I havent used it either, though i think its biggest payoff is with large app suites like CS when they go universal. or if you have an pb with a 60 gig drive or less. freeing up a few hundred megs can give you more swap, room for photos or what not.


I am in your boat, Nick. Saw this on MAAD, but got it already in the GiftZot. I have it loaded, registered and sitting in my dock, but I can’t bring myself to run it, for the two reasons you listed. I am not sure that I trust it not to chew some code that it shouldn’t, and freeing up a few megs doesn’t seem to be worth it. Perhaps if I had a small hard drive, but with 160 GB on my MBP, it doesn’t seem to do much. Looking forward to hearing from some users, perhaps I can be convinced to try it out.

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