Though it's not easy to hack into or break through a Mac's security, it is possible, especially if someone accidentally installs malware without realizing it. If your Mac is running slow or you're seeing unusual advertisements within your web browser you might have accidentally installed malware at some point. Don't worry. It happens to the best of us (not me, of course). There are things you can do without having to burn it all down.
When you look at the Mac models in Apple store, all types (Macbook, Macbook Pro and Macbook Air) are sold starting from 512GB. This is a decent storage space for a solid state drive (SSD). But the storage space can quickly wiped of based on your usage over the period of time.
The problem: Mac malware in the Library folder
Serenity Caldwell writing for iMore in 2017:
My father-in-law's MacBook Pro had been running into curious slowdowns for a two-year-old laptop and he kept on seeing weird sites taking over his Safari and Firefox search bars. It was clear to me that his browser had been hijacked.
We got rid of the browser hijack pretty quickly — I suggest using Cella's excellent how-to if you ever run into a browser hijack yourself — but the slowdowns were more curious. Upon further investigation, I found a couple of self-professed 'Mac security programs' that popped up, demanding money to 'clean your Mac from junk'.
Spoiler: These programs were the junk. And worst of all, they'd seemingly added a bunch of nonsense files into this computer's Library folder, with random folder names like 'prestidigitation' and 'beeswax'.
Now, I want to preface: I'd never seen an attack like this on a Mac before in my life, and finding this kind of full-Mac hijack is very rare. It's likely that he accidentally installed one of these 'security' programs (or had it installed), which spiraled out of control from there.
These hijacks didn't appear to be able to do much beyond slow down his machine with endless failed attempts to run a program — the process didn't have admin permissions, so it couldn't execute a thing from the library. But because they were there, they were constantly crashing aspects of his Mac. I knew I had a malfunctioning laptop on my hands, so I turned to my age-old troubleshooting checklist.
How to fix a corrupted Mac
If you're working on a computer that has slowed down beyond reasonable aging or is otherwise acting beyond the pale, here are my favorite tactics you can take to try and restore it to its former glory.
Update the system software
This is almost always the first thing I do when troubleshooting Macs: Chances are, the user hasn't installed a security update or other software updates that may be slowing their computer to a crawl.
Click on the Apple menu icon in the upper left corner of the screen.
Select App Store to open the Mac App Store.
Click on the Updates tab at the top of the Mac App Store window.
Install all relevant updates. (You may need the Apple ID and password for the machine.)
If the computer is running macOS Sierra, you can avoid having to do this troubleshooting step in the future by turning on Automatic Install in System Preferences, which can automatically download newly available updates in the background, and install them overnight.
With the Mac App Store open, click on App Store in the upper left corner of the Menu bar.
Click on Preferences.
Under Automatically check for updates, check the following boxes:
Download newly available updates in the background
Install app updates
Install macOS updates
Install system data files and security updates
Check the disk for errors
If software updates aren't doing the trick, the next thing to check is the hard drive itself. With Apple's Internet Recovery partition, fixing a cranky drive is an easy process.
Restart your Mac.
During reboot, hold down Command-R until it starts up.
Once rebooted, you should be in the Internet Recovery Partition. Select Disk Utility.
Click Continue.
In Disk Utility, click on the First Aid button,
Click on Run to execute.
Your Mac will then run a cursory check on its hard drive to determine if there's anything wrong — and if so — if it can fix it.
Reset the NVRAM/PRAM and SMC
If neither app updates nor disk repair are helping, sometimes a good cache flush can get your Mac running just a bit more smoothly.
To reset the NVRAM (or, on older Macs, PRAM), reboot the Mac and hold down the following keyboard command during startup for at least twenty seconds: Command-Option-P-R.
After you reset your NVRAM, you may be required to reconfigure some system settings (like sound and time zones), which are stored in that cache.
An SMC reset is a bit more complicated, and Apple recommends it only after all other troubleshooting avenues have been exhausted.
If you're using a laptop:
Shut down your Mac and plug it in.
Restart the computer by pressing the Power button along with the keyboard command Shift-Control-Option.
Release these keys, then just press the Power button to properly start your computer.
If you're using a desktop:
Shut down your Mac.
Unplug it and wait for at least 20 seconds.
Plug the Mac back in and wait 5-10 seconds.
Restart your Mac with the Power button.
Partition your disk (or erase it)
After exhausting all other avenues, this was the solution we came across to properly fix the broken laptop. The hard drive had been so corrupted by these 'security' programs that there was nothing I could do to fix it. When Safari launched over the login screen after a reboot, I knew my usual fixes wouldn't work: It was time to bring out the big guns.
In most cases, I'd grab an external drive, back up the corrupted disk, then wipe the drive clean with the Internet Recovery partition and start over. But there were a couple of reasons that wouldn't work here:
We were on vacation, and lacking any sort of external media.
With a semi-corrupted disk, we couldn't just clone the user folder and restore the new disk from a backup — we'd have to do a clean install, which meant moving files over one by one. If we'd missed something and moved all the old files to an external drive, my father-in-law would have had to carry it everywhere just in case.
Given that this laptop had a 500GB hard drive — only 40GB of which was being used — I had an alternate idea: I'd partition the drive, again using Internet Recovery, and install macOS Sierra on the new partition. Essentially, it would be a 'clean' new computer for my father-in-law to work on, but all the original data would still exist on the old partition in case he needed to grab a file.
Note: In order to partition your drive, you'll need enough free space on your drive to do so — at least 30GB. If you're light on space, you may want to back up your corrupted disk to a USB drive, instead.
How to create a partition on your Mac
Open Finder from your dock.
Select Applications.
Scroll down and open the Utilities folder.
Double-click to open Disk Utility.
Select your hard drive in the Disk Utility window. It will be the first drive on the list. It might be named 'Fusion,' or 'Macintosh HD.'
Click on the Partition tab.
Click the plus (+) button.
Change the size of the partition you wish to use by dragging the resize controls. The used space is represented in blue.
Name the new partition.
Click apply.
Disk Utility will check the disk and make changes. This will take several minutes.Disk Utility will then make the changes. After that's completed, quit Disk Utility to return to the main Internet Recovery menu.
Click on Reinstall macOS.
Click Continue.
Click Agree to agree to Apple's licensing agreements.
Choose the New Mac hard drive as the disk you'd like to install macOS onto.
Press Install.
The Mac will download a fresh copy of your operating system from the App Store and will install it. The speed of this process entirely depends on your Mac's connection speed to the Internet. You can wait an hour or longer on a slower connection.
Your Mac will restart automatically into the new partition once the software has downloaded, then the installation of the operating system will continue.
After you finish setting up the new hard drive, it's time to move your files over. Because of the way partitioning works, your old hard drive partition will show up next to your currently-active partition, just like an external drive; you can then grab any files you need from it.
Launch a Finder window.
Under Devices in the sidebar, locate your original Macintosh HD.
Copy any files you'd like to keep from your old hard drive to the new machine.
Note: If you want to copy over applications, I'd strongly suggest redownloading them from the source — the Mac App Store or the company's website — rather than trying to copy them over from the old partition.
From here, you can follow instructions for setting a Mac up from scratch when it comes to installing and customizing anything else.
I generally recommend keeping the old drive partition around for at least a few months in case you or your family member forgets to move something over; after that period, however, you can easily delete the old partition and move to the new partition full time.
Consider additional anti-malware protection
While malware on the Mac is rare, it does crop up, as we've demonstrated. Having the right tools to get rid of malware can be an important part of keeping your Mac safe and secure. There are a number of tools that you can choose from, including popular programs like BitDefender and Kaspersky, that will help you keep malware from infecting your Mac.
Questions?
Do you have any must-follow troubleshooting steps? Let us know in the comments.
Updated July 2019: Added a sub-section regarding anti-malware protection.
Serenity Caldwell contributed to an earlier version of this guide.
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CleanMyMac is an app that monitors your system and recommends data to purge. With one click of the Scan button, you can dump gigabytes of built up caches, unused apps, mail attachments, temporary memory, and a whole lot more.
On Wednesday, MacPaw released a major update to CleanMyMac X that completely changes the interface, adds a few awesome new features, and continues to provide an easy way for you to clear out your Mac's junk.
CleanMyMac X
Price: $40 for a one-year subscription; $90 for one-time purchase
Bottom line: CleanMyMac X is definitely MacPaw's best version of the Mac cleaning program so far
The Good
Recommends things for removal.
Beautiful interface
An updated menu shows off a lot of information.
The bad
Some minor functions are confusing.
A little pricey for some.
What's new in CleanMyMac X?
I know I don't need CleanMyMac. I can do all of the cleaning actions it offers myself by going into different files and manually deleting things. Since macOS Sierra, Apple even offers its own version of a Mac cleaner with Optimize Storage, Reduce Clutter, and Empty Trash Automatically. That being said, I love CleanMyMac because it's so much easier to use than digging around my system, removing old files, clearing caches, deleting cookies, freeing up memory, and all the other Mac cleaner tools that it does for me with just a click.
I've been using CleanMyMac since 2015. It has never caused me any slowdown issues, nor has it ever automatically deleted a system file that it shouldn't have. It's always worked great and been easy to use. With version X (pronounced ex) there are new tools, better junk scan, faster search, and more.
Complete redesign - CleanMyMac has an all-over redesigned look. Though it's got an updated look, the tools you need are still in the same place. So if you're updating from version 3, you won't feel lost in the woods with this new design.
Better algorithms for scanning for junk - With years of experience and a better understanding of how we use the program, MacPaw's team created a better algorithm for scanning for junk so it is more likely to find something in your Mac that you don't need hanging around.
Malware scanner - CleanMyMac X will check for malicious files, viruses, and more. If you think something may be lurking around in your system that doesn't belong, CleanMyMac X's malware scan can seek it out.
Faster scan - CleanMyMac X has an improved scan time of up to three times faster. That first time you look for junk will take a lot less time than it used to.
Separate tools for updating apps - In the latest version of CleanMyMac, you can quickly see apps that haven't been used in a long time, but you can also see apps outside of the Mac App Store that need an update. Click the Update button right from the updater to get up to date.
Personal assistant - When you perform a scan, a little chat bubble appears and offers additional suggestions for clearing out junk that you may want to do next. You can find the personal assistant in the upper right corner of the window at any time. Click it for suggestions.
CleanMyMac Menu redesign - The Menu bar widget has a whole new look with more information available at a glance. See how much hard drive space you have, how much RAM you're using (with a shortcut to free up memory), how full your trash is (with a shortcut to empty it), your processor load and what apps are weighing it down, your network speeds (with a shortcut to test your wi-fi speed), and the ability to monitor how much space you're using in Dropbox.
What I liked
One of my favorite moments testing out CleanMyMac X was when I was using the app updater. It showed that Malwarebytes needed an update, but when I clicked on the update button. Nothing happened. I double-clicked on the Malwarebytes icon in CleanMyMac X and it opened Malwarebytes. The prompt said I needed to update to version 3, which I knew I had already done. So, I right-clicked on the Malwarebytes icon in CleanMyMac X and selected 'Show in Finder.' Sure enough, there were two versions of the app. I was able to find the old app and delete it in just a couple of clicks!
The app uninstaller actually has a specific section for 32-bit apps on your Mac. macOS Mojave will be the last Mac operating system to support 32-bit apps. I quickly removed about 60 apps that I won't be able to use again in a few months anyway, whether I like them or not.
When you go through individual scan-and-remove tools, you can see what's being recommended for removal and decide for yourself whether you want to delete it. For example, in the iTunes Junk scanning tool, CleanMyMac X will scan iTunes for broken downloads, old software updates, and iOS apps you may still have stored on your Mac (from back when you could do that sort of thing). After the scan, you can review the details and manually decide whether you want to delete such things as old iPhone backups (I deleted about 25GB of old iPhone backups, but saved one that I have for my SE).
The first and most obvious change to CleanMyMac X is the interface. It's got a lot of rounded corners, brightly-colored icons, faux transparent backgrounds, and a nice ombre effect throughout. It's simply beautiful. I never had a problem with the version 3 interface, but now that I've been using the version X interface, the old one looks like an outdated pair of jeans - you still like the way they look, but wouldn't be caught dead wearing them in public.
The updated Menu bar widget is one of my favorite changes to CleanMyMac X. Anyone who knows me knows that I love a good Menu bar widget. CleanMyMac Menu now shows you lots of useful information about your Mac's system and most categories include a shortcut to cleaning up a process. You can free up memory, remove trash, and run a speed test on your network, all right in the Menu bar widget.
If you want to add anything scanned to the 'Ignore' list, you can right click on it and your recommendations will stop telling you to review those files. It really helps when you're trying to scratch that itch to do everything recommended. Getting that 'All Clean' response is so very satisfying.
What I didn't like
There are some minor functions that confused me just a little bit. For example, when I deleted the duplicate, older Malwarebytes app directly in Finder, it still appeared in CleanMyMac X until I quit and restarted it. Additionally, there is one app I use on a very regular basis that is listed on the 'unused' section of my app list. Though CleanMyMac X is fairly good at reading what's in your system, it's a good idea to always review files to make sure you understand what's being suggested to remove, - something that CleanMyMac does recommend for each tool.
Conclusion
CleanMyMac X is definitely MacPaw's best version of the Mac cleaning program so far. It looks great, works great, and has dozens of features you can manually trigger. If you don't want to go through the tools individually, you can run a smart scan and quickly remove junk and free up hard drive space and memory.
It's not the cheapest software around at a retail price of about $90 for a one-time purchase or $40 per year for the subscription. Everything that you can do using CleanMyMac, you can do yourself if you know your Mac well and aren't afraid of Terminal.
If, however, you'd rather have a program that does it all with one click, you can get CleanMyMac X at a massive 30-50% discount right now during MacPaw's 10-year anniversary sale. New users get 30% off at $28 for the yearly subscription or $63 for a one-time purchase. Upgraders from CleanMyMac 3 get 50% off the upgrade at $45 for a one-time purchase. If you're switching to the yearly subscription at this time, you can lock in a $20 price for one year.
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