What about Clean My Mac 3?

I tell a lie. Having run it again, it was 15GB.

Roughly 33% System, 33% Photo (cache), and 33% iTunes (cache)

I'm not in a position that I'm running out of SSD room so not in a rush to delete any of this and likely won't. But it's useful to know.

33% system what?

Those caches are not Junk, and removing them makes your Mac slower, not faster. There is a case for removing caches - exactly one case: if a cache is corrupted. If it's not then it's an utterly pointless exercise because caches are used to help your Mac run faster, and, once removed, must be rebuilt, so you lose speed as that happens. It's a classic example of an app that has a "feature" that no one routinely needs. There is zero case for routinely trashing caches.

So, we can establish that 2/3rds of what it found as "junk" demonstrably isn't. What about the other 1/3d?

I understood the main purpose of CMM to be about reclaiming disk space so the removal of a large cache, even if it's temporary, could be of use to someone.

Haven't got the time or motivation to list the System stuff but primarily language files.

Honestly, I'm not that bothered about what folks think of this app and whether they chose to use it or not. I just think it's a bit dodgy banding around terms like 'malware' when it can't be justified. I suspect if I deleted Office, my Mac might speed up.

...but primarily language files

Removing language files can affect an app working in some cases, and also affect updating. But CMM doesn't know the cases, and so, becomes a sledgehammer cracking something that resembles a nut but isn't. So, another "feature" of dubious quality.

I understood the main purpose of CMM to be about reclaiming disk space so the removal of a large cache, even if it's temporary, could be of use to someone

If a person's use of the Mac is so particular that s/he needs to temporarily recover disk space for a project, that person won't be using an app to do it, they'll be knowledgeable enough to do it themselves, and to do it selectively, depending on what exactly they are trying to do. But that kind of user is not the target market for this app, is it? The person buying this app is doing so precisely because they don't know how to do these things, or understand the effect of doing them. So, their business model is to separate the unwary and inexperienced user from their his or her cash by offering "features" that are not required - at best - and actively dangerous at worst.

There are a couple of the reasons experienced users on here warn about these apps, right there...

You say ...

I just think it's a bit dodgy banding around terms like 'malware' when it can't be justified.

But that simply isn't true either. As my post of 10.01 said , after its removal there is an immediate and substantial improvement.

This is verified by the number of people who later mark their posts as solved.

But I think your initial post was less a considered comment than some gentle stirring of the pot. At which point I'm off.

if you have a 250Mbps LAN - fully possible on 5G, and your disk is running at 40MBPS, drop using the disk on the MAC and get a NAS server. and get this running at full speed.

If you have say 100Mbps Internet access, then set cache size to 0, checking it is just wasting time, it is twice as fast to get it from Facebook, as long as your ISP can deliver this.

10Mbps here is the same as 10Mbps there. The problem is bottle necks - whatever everything has to visit in order to get things done. My favourite example is "AdBlock" in your browser and all "extensions". there more "extensions" the slower it goes.

Posted my own thread yesterday, this was the Etrecheck from one of the imacs yesterday.

I keep getting system has run out of application memory because of mail

Don't use it.

For more information about maintaining your iMac:

Maintaining Mac OS X - The X Lab

The Safe Mac » The myth of the dirty Mac

Not a good idea to use any kind of 'cleaning facility' like this. Do some digging, go to Google and read the reports then compare those reports with what you will find on Apple Forums. We are not anti - all things non Apple, but when you buy a Mac you are buying a totally different and in many people's eyes, superior system.

Your Mac will look after itself; just let it.

One thing I was surprised to find after buying my first mac (iMac last month) is how bizarre and seemingly incomplete the "uninstall" procedure is for OS X.

I'm the type of user with Windows who would uninstall a program, then go hunt for any left behind folders. Over the years uninstallers have improved immensley and they get rid of everything 95% of the time.

But with OS X, you just drag and drop the main icon into the trash, which at first I thought was BRILLIANT, but then I found that almost every piece of software left all their main folders behind, eating up space on the hdd. I found a youtube video that shows how to manually go in and keep things clean after "uninstalls", but I didn't think this was necessary on the Mac side of things. Over time wouldn't you need a proper way to clean things up and prevent the OS from slowing down (and losing hdd space?)

How to maintain a Mac

1. Make redundant backups, keeping at least one off site at all times. One backup is not enough. Don’t back up your backups; all should be made directly from the original data. Don’t rely completely on any single backup method, such as Time Machine. If you get an indication that a backup has failed, don't ignore it.

2. Keep your software up to date. In the App Store or Software Update preference pane (depending on the OS version), you can configure automatic notifications of updates to OS X and other Mac App Store products. Some third-party applications from other sources have a similar feature, if you don’t mind letting them phone home. Otherwise you have to check yourself on a regular basis.

Keeping up to date is especially important for complex software that modifies the operating system, such as device drivers. Before installing any Apple update, you must check that all such modifications that you use are compatible. Incompatibility with third-party software is by far the most common cause of trouble with system updates.

3. Don't install crapware, such as “themes,” "haxies," “add-ons,” “toolbars,” “enhancers," “optimizers,” “accelerators,” "boosters," “extenders,” “cleaners,” "doctors," "tune-ups," “defragmenters,” “firewalls,” "barriers," “guardians,” “defenders,” “protectors,” most “plugins,” commercial "virus scanners,” "disk tools," or "utilities." With very few exceptions, such stuff is useless or worse than useless. Above all, avoid any software that purports to change the look and feel of the user interface.

The more heavily promoted the product, the more likely it is to be garbage. The most extreme example is the “MacKeeper” scam.

As a rule, the only software you should install is that which directly enables you to do the things you use a computer for — such as creating, communicating, and playing — and does not modify the way other software works. Use your computer; don't fuss with it.

Safari extensions, and perhaps the equivalent for other web browsers, are a partial exception to the above rule. Most are safe, and they're easy to get rid of if they don't work. Some may cause the browser to crash or otherwise malfunction. Some are malicious. Use with caution, and install only well-known extensions from relatively trustworthy sources, such as the Safari Extensions Gallery.

Never install any third-party software unless you know how to uninstall it. Otherwise you may create problems that are very hard to solve.

4. Beware of malware. Malware is malicious software that circulates on the Internet. This kind of attack on OS X used to be so rare that it was hardly a concern, but it's now increasingly common, and increasingly dangerous.

There is some built-in protection against downloading malware, but you can’t rely on it — the attackers are always at least one day ahead of the defense. You can’t rely on third-party protection either. What you can rely on is common-sense awareness — not paranoia, which only makes you more vulnerable.

Never install software from an untrustworthy or unknown source. If in doubt, do some research. Any website that prompts you to install a “codec” or “plugin” that comes from the same site, or an unknown site, is untrustworthy. Software with a corporate brand, such as Adobe Flash Player, must come directly from the developer's website. No intermediary is acceptable, and don’t trust links unless you know how to parse them. Any file that is automatically downloaded from the web, without your having requested it, should go straight into the Trash. A web page that tells you that your computer has a “virus,” or that anything else is wrong with it, is a scam.

In OS X 10.7.5 or later, downloaded applications and Installer packages that have not been digitally signed by a developer registered with Apple are blocked from loading by default. The block can be overridden, but think carefully before you do so.

Because of recurring security issues in Java, it’s best to disable it in your web browsers, if it’s installed. Few websites have Java content nowadays, so you won’t be missing much. This action is mandatory if you’re running any version of OS X older than 10.6.8 with the latest Java update. Note: Java has nothing to do with JavaScript, despite the similar names. Don't install Java unless you're sure you need it. Most people don't.

5. Don't fill up your boot volume. A common mistake is adding more and more large files to your home folder until you start to get warnings that you're out of space, which may be followed in short order by a boot failure. This is more prone to happen on the newer Macs that come with an internal SSD instead of the traditional hard drive. The drive can be very nearly full before you become aware of the problem.

While it's not true that you should or must keep any particular percentage of space free, you should monitor your storage use and make sure you're not in immediate danger of using it up. According to Apple documentation, you need at least 9 GB of free space on the startup volume for normal operation.

If storage space is running low, use a tool such as OmniDiskSweeperto explore the volume and find out what's taking up the most space. Move seldom-used large files to secondary storage.

6. Relax, don’t do it. Besides the above, no routine maintenance is necessary or beneficial for the vast majority of users; specifically not “cleaning caches,” “zapping the PRAM,” "resetting the SMC," “rebuilding the directory,” "defragmenting the drive," “running periodic scripts,” “dumping logs,” "deleting temp files," “scanning for viruses,” "purging memory," "checking for bad blocks," "testing the hardware," or “repairing permissions.” Such measures are either completely pointless or are useful only for solving problems, not for prevention.

Let go of the Windows mentality that every computer needs regular maintenance such as "defragging" and "registry cleaning." Those concepts do not apply to the Mac platform.

The very height of futility is running an expensive third-party application called “Disk Warrior” when nothing is wrong, or even when something is wrong and you have backups, which you must have. Disk Warrior is a data-salvage tool, not a maintenance tool, and you will never need it if your backups are adequate. Don’t waste money on it or anything like it.

What are thoughts about Clean My Mac 3?

I think it will be 50% worse than CleanMyMac2.

Drisley - it all depends on how the app is written. Well-written apps should be gone of you drag them to the trash. If there a couple of plist files left behind, they will take up no significant disk space, and casue no harm.

I know this is a little late but several things here.

One there is NO "Clean My Mac 3" as far as I can tell; CleanMyMac2 is latest in that line.

Second, let's be honest here, the software Apple provides for maintenance is bare bones at best when it exists. Couple that with people who have no idea on how to write programs for the MacOS and have the program drop files all over the hard drive as if they were on Windows and you have a problem.

So there are there are a handful of “cleaners,” "doctors," "tune-ups," etc that are useful: TechTool Pro (which at one time was part of the Apple Care package) and the aforementionedCleanMyMac2 being the more bang for your buck ones.

Third, if you like me have moved your files form Mac to Mac over the years you are going to have files that will cause weird behavior in the OS. CleanMyMac2 was able to find an old OS X extension I didn't even known I still had and it removeal stopped some really flaky behavior of the OS.

Clean My Mac 2 is great as long as you can cope with the damage it does. But if you can cope with that, then you won't need it anyway. There is nothing it can do that you can't do yourself, for free and more safely. Search the forums for the many many threads on the subject. It's expensive junk. Avoid.

And how come the folks who recommend always have very few points, and the folks who advise against have very many? Coincidence that.