xslimmer.jpg Hard disk space can be extremely valuable, especially for notebook owners. I find myself constantly auditing the contents of my disk, usually with tools like GrandPerspective and WhatSize to find the gremlins that are munching on my available space. Of course my Applications folder always pops up as the biggest offender, but there’s nothing I can do about the whopping 4 GB required for stuff like Final Cut Studio 2, right? I mean, every line of code under the hood of Motion is being used isn’t it?

Apparently not. A little app called Xslimmer claims to free up wasted disk space by removing unnecessary code from Universal Binaries that doesn’t fit with your machine’s architecture. It will also remove unneeded languages from various apps (Adium, for example, has over 20 languages according to Xslimmer’s site) to help slim them down and recover your disk space.

How it Works

Xslimmer’s interface is extremely straightforward. You simply drag applications onto Xslimmer and in analyzes each one to see if it can be slimmed. If the app can be slimmed, Xslimmer will display the current size of the app and it’s estimated “slimmed” size. Some applications cannot be slimmed because there is no extra code or languages, or its on Xslimmer’s blacklist (which, as the name implies, are applications that are not allowed to be slimmed for various reasons). For example, most of CS3 sits on the blacklist:


You can add apps one by one or use the “Genie” to scan your entire disk for potentially fat binaries. When you’re ready, click the “Slim!” button and you’ll be prompted with a warning to back up your applications. You can choose to have Xslimmer save backups somewhere locally, so that you can make sure all applications run as expected after slimming and restore them if needed. Restoring is a simple process – just click the “History” button, and click the restore icon in the history dialog.


The Skinny

I was able to save 2.5 GB from 95 applications in less than ten minutes (though I won’t see my real disk savings until I nuke my backups). That beats the heck out of the 100mb or so that it would take me hours to free up by sifting through all my documents that might be scattered across my machine. Even better, your apps will run the same or even faster than they did before slimming (though there are potentially applications that will not run after the slimming process – good thing the backups seem to be sound).

Overall, Xslimmer is extremely intuitive and kind of fun to use, especially when you see some of the notable savings:

Automator: 28.7mb to 2.95mb
Calculator: 13.4mb to 1.59mb
Disk Utility: 32.7mb to 3.88mb
DVD Player: 42.7mb to 6.48mb
iTunes: 129mb to 31.4mb
Preview: 70.1mb to 9.71mb

At $11.95, Xslimmer is a steal. My only real gripe is that you can’t slim Adobe CS3 apps, but I think that’s something to take up with Adobe and not Xslimmer. You can try a demo and save up to 50mb, if you wanna take it for a test drive before you drop the cash. I would strongly suggest that you make sure that all your apps run as expected after slimming though. I haven’t experienced any issues yet, but better safe than sorry.


Gaby J

XSlimmer is amazing. I had half a GB left on my 120 GB Hard Drive (White MacBook, 2.2 GHz Intel Core 2 Duo, 1 GB Ram) and it saved me so much space. Especially with Microsoft applications. Other than XSlimmer, I recommend going through your library and removing fragments of old applications and crap that you don’t need. I now have 15 GB of free space after removing unnecessary junk.

James Levine

What I’m getting from this discourse is that more is not nec. better. The developer here took a lot of care to identify code that was extraneous. On the other end of your options is monolingual, which in the past has forced me to commit to a complete clean system re-install. The difference is like a scalpel and an axe, if you want to borrow a metaphor from the campaign trail.


It is better because it does more than Xslimmer. It also compresses images and removes debug information. From my experience, it cleard a MB or so more in an app than Xslimmer. It isn’t much, I agree with that.

Remeber it’s free.

What I like in Xslimmer and miss in Trimmit is the better interface and the wizard for finding/slimming more apps at the same time.

Trimmit is still beta.


#14. Is that based on your experience, an educated guess, or simply an opinion with no foundation?


As Nick and Harley said, Trimmit is way better and it’s free. Only problem you might find with it is that it lacks multiple slimming on a GUI.


Overall, Xslimmer is extremely intuitive and kind of fun to use, especially when you see some of the notable savings

I’ve found that Vacuous Virtuoso’s Trimmit does a much better job at removing bloat and recovering disk space. It also has a 100% failsafe backup system.


“Sorry to hear that folks have had issues with programs like this.”

Sure. I notice the guy now says:

“I use both Power PC and Intel Macs and this caused issues as well when copying apps.”

Of course, if that’s if that’s your use-profile you don’t want to be stripping out architectures. Those who don’t need to move application bundles between machines with different architectures should be fine. Not “will be” but “should be” … there are exceptions. And do stay within limits. The same poster also mentions Monolingual, and says he doesn’t know if it was that that caused the problem. Possibly it was: on the Monolingual site they note:

“… you should not strip the System frameworks [on an Intel Mac] if you want to use Rosetta.”


Quite so. Microsoft Office would, of course, be using Rosetta.

And as has been said, there are apps that don’t like having stuff removed. Adobe has already been mentioned. One suspects there could be issues with Skype, as that is known to check its integrity on launch (hence its problem with the Leopard firewall). I’ve also noticed that Pacifist will complain if it thinks it’s been corrupted, as it might do when being cleaned.

Bottom line: as Matt advised, make sure you have backups.

But there’s nothing wrong in itself with slimming down application bundles. It’s not second-guessing Apple. Apple itself makes a widget in the GUI available for removing languages. (See “Languages” on any application bundles “Get Info” panel — removing unwanted languages is what the “minus” sign is there for.) These apps merely automate the process.

And lipo is there on the command line, made available by Apple themselves, specifically for removing architectures.


Applications like Monolingual, one imagines, remove architectures by making use of lipo.

I’d suggest this blog might also like to take a look at Ankur Kothari’s Trimmit:


Trimmit has a few other tricks up its sleeve. It looks for redundant files that are put there in the build process but are not supposed to be distributed. It checks whether a developer has used a “debug” build — again developers are not *supposed* to distribute debug builds but some are lazy enough, or uniformed enough, to do so. Trimmit can also apply lossless compression to tiff files. Mac apps tend to have a lot of tiffs in, and although Apple provides a utility at the command line for compressing tiffs not all developers use it.

Stephanie Guertin

I love XSlimmer – I try out tons of apps, and XSlimmer saves me a ton of space, both before in Tiger and now in Leopard.
Also, FYI, the reason you can’t slim Adobe apps IS an Adobe thing – if you modify their code in any way, the software won’t run. Given other decisions the company has made, I suspect it’s an attempt to prevent piracy.


Nice app. It has never given me a problem either, and the risk is really limited. At maximum you would have to restore or reinstall an application.

It has saved me 4Gb in my Macbook. I am really happy with it.

Matt Radel

Sorry to hear that folks have had issues with programs like this. As I said, I’ve had no issues since slimming my apps, and the backup system seems to be extremely sound.

I’ll keep tabs on everything and post any updates if necessary.


Yes I used an earlier version of Xslimmer and another app called monolingual, I had back ups although the additional time and initial frustration was horrid.

I use both Power PC and Intel Macs and this caused issues as well when copying apps.

I downloaded this version of Xslimmer and it seems to have gained some good features and improvements under the hood.

I think my advise should be modified to make a complete back up and remove only those items you surely do not need.

Marc Orchant

Like Ingo (#3), I have used XSlimmer on a number of systems running both Tiger and Leopard with zero problems. I have hundreds of applications installed (I do a lot of reviews) and have never, not once, had an application fail due to slimming. In aggregate on my two current Macs (both running Leopard BTW) I have saved over 4GB of disk space.

To steiner (#2) – it’s not a question of whether or not “Apple knows what it’s doing”. The reason these apps can be slimmed in inherent to the Universal Binary format introduced to support both Power PC and Intel Macs. There’s lot of extra code being installed on both types of systems that’s never used. Great for developers who want to support a wide base of users with both old and new hardware. In no way useful to end users once the application is installed. And I beg to differ. Saving 2GB of space on a 120GB hard drive is not inconsequential.

I’ve slimmed MS Office on four different systems with no issues. Not sure what languages you nuked that caused your problem and I’d be curious if you did that some time ago with an older version (Xslimmer is updated frequently and better sensitivity to language components was a fix a while back) and more importantly, whether you followed Matt’s very good advice to use the Backup feature so you could easily restore, rather than having to reinstall.



Xslimmer (ironically) is over 80% junk, going from 5 MB on disk to a meagre 1 MB after being cleaned. In this case, the disk image is three times as big as the cleaned, uncompressed app.


I’ve been using Xslimmer on Tiger and Leopard and never encountered any problems. Great program and well wort the $$$.


This is potentially dangerous, I ran it while on TIger and it removed language packs that were needed in Office 2004 and it never worked thereafter. I had to do a complete reinstall.

Be careful if this program removes architectures in any way in Leopard, this will ruin your system for sure and could brick your system. This is due to signed applications and the sandboxing and security features in leopard.

I am staying away from all these slimming pgms.

Apple knows what they are doing, most hard drives are fast enough and for the 200MB of space rather delete or move some of those old ripped movies that you are not watching any more. Or stip iTunes of half the library that you are not listening to anyways.

well that is my 2c, basically stay away from this app and others like it or it will cost you not only the license but a new system and at worst new hardware.


The reader should be aware that in Leopard applications will be digitally signed so if they are altered they may not run properly. I only changed my icon for safari and I constantly got an error message telling me to reinstall safari so I’m not sure what removing the architecture would do.

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