Who’s Been Using Your Mac Behind Your Back? Find Out!

Justin Pot 21-09-2013

Suspect someone’s been using your Mac when you’re not around, even though you told them not to? Find out, without the need for special software.


You could physically dust your Mac for fingerprints, of course, but if you lack the gear for that don’t worry: there are digital tools you can use for this detective work. You’ll be amazed at what you can find out just by checking logs and looking at recently open documents and applications.

Ryan recently showed you how to check if someone’s been using your PC 4 Ways to Tell If Someone Was Snooping on Your PC Your computer is not how you left it. You have your suspicions, but how can you tell if someone was snooping on your PC? Read More , but it didn’t take long for all of you to ask about doing the same thing on the Mac. Here’s how you can tell if someone’s been using your OS X computer.

Step 1: Check The Logs

Your Mac logs a lot of things. Obsessively. Open up the Console if you don’t believe me – this app gives you a simple way to explore a wide variety of logs. You’ll find it in Utilities, which is in your Mac’s Applications folder. Open it up for the first time and you’ll mostly see gibberish:


It’s almost a record of everything that ever happened on your computer, and it can be completely overwhelming.


So, how does this help you? If you can narrow it down to just relevant points of information, a lot. Perhaps the most helpful thing is to see a list of every time your computer woke up, and doing just that is simple. Type “wake reason:” into the search bar and you’ll see when that happened:


Click the “earlier” button at the bottom to go further and further back into time. You know something might be fishy if your computer woke up some time while you were out of the house.

There’s a quicker way to do this, if you’re comfortable with the Terminal: just type syslog |grep -i "Wake reason" and you’ll see a longer list:



Knowing when your computer wakes up might not be enough – cats pressing keyboard keys can be enough to prompt this. But if you’re using a MacBook you’ll know exactly when someone opened it to use your computer, and that’s helpful.

This won’t tell you who is using your computer, of course, or what they did. But it’s a good place to start.

Step 2: Check Recent Items

Your Mac keeps track of recently opened applications and documents. It does this mainly to help you quickly access them again, but it’s also really useful if you suspect someone else is using your computer. After all, they’ll probably be interested in different applications and documents than you are.


See a list of all recent applications and documents by clicking the Apple logo at top-right, then hovering over “Recent Items”. You’ll see a list:


Hold Command and you can click to see these files in Finder, giving you access to information like when they were last opened.

Speaking of: newer version of OS X offer similar functionality to this in the Finder itself. You’ll see recently opened documents, pictures, movies and more broken down into categories on the All My Files shortcut:



If you find something here you know you didn’t look at recently, congratulations: you’ve got one more piece of evidence that someone else is using your Mac while you’re not around.

There are other “Recent” things to check, of course, beyond what your Mac records on its own. Your web browser, for example, includes a detailed web history. Applications like Microsoft Word and InDesign have their own list of recently opened documents. Check these and other things if you want to gather further evidence.

Bonus Step 1: Install Snooping Software

If this isn’t telling you enough, and you suspect the unauthorized usage is ongoing, you could install some snooping software to find out what’s going on. Prey lets you monitor computer usage Use Prey & Never Lose Your Laptop Or Phone Again [Cross-Platform] Here’s the thing about mobile and portable devices: since they aren't tethered to anything, it’s almost too easy to lose them or, worse, have them stolen from right under your nose. I mean, if you... Read More from any other device connected to the web. You can take screenshots to see exactly what’s going on with your Mac while you’re away from it. Heck, you could even use it to take a picture of your moocher, using the built-in webcam.

Alternatively you could just use Chicken of the VNC How To Set Up & Use Chicken Of The VNC For Remote Access [Mac] If you've ever needed to get remote access for a computer, you've probably realised that some solutions are far superior than others. Even as far as VNC (Virtual Network Computing) clients go, there are a... Read More or any remote software to watch what’s happening on your computer while you’re away.

Bonus Step 2: Kill It With Passwords

But there’s an even simpler solution: lock your Mac with a password. If you don’t want people using your computer behind your back this is the most effective means of doing so.

If you’d rather not do that, however, you should get a pretty good idea of who’s using your Mac with the first two steps – between the logs and the recent apps a decent detective should be able to rule out most major suspects. The rest, of course, is up to you – unless you use Prey to capture a picture of the culprit.

If you have the same concerns about your phone, check out these apps that can catch snoops trying to get into your phone.

I want to know which tools you think are most useful for this job, and which have worked for you. Share your battle stories in the comments below.

Image Credits: Willow and the Mac Via Flickr

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  1. Bo
    October 3, 2016 at 1:50 pm

    I would like to see when I turned on my mac and turned it off to check how long approximately I have been in the office. Console looks different on MaxOS Seirra, is there any way to check this now?

  2. Anonymous
    June 30, 2015 at 1:33 pm

    How could I find out if someone has backed up my macbook air to an external hard drive/stick? I have not backed it up in this manner since purchase but am beginning to wonder if someone else has...? Answer for idiots please, as you can tell I am not very tech savvie Thanks

    • Justin Pot
      June 30, 2015 at 5:04 pm

      If you didn't set up a backup yourself no one else has run one, but you could head to the Time Machine panel of the System Preferences and see if there's a drive set up.

      • Anonymous
        June 30, 2015 at 5:17 pm

        Thank you Justin heading over there now....

  3. D. Floyd
    March 18, 2015 at 3:23 pm

    I have had my MacBook since 2008. She is still awesome even though I am pretty hard on her. But she can be so slow sometimes. Is it possible or even recommended to defrag a Mac? Or something else I can do to fix this?

  4. D. Floyd
    March 18, 2015 at 3:15 pm

    This was very helpful. Thank you! I think that guy has Apple Envy. :)

    • Justin Pot
      March 18, 2015 at 3:18 pm

      Maybe? Not sure why anyone gets worked up over computer preferences, use what works for you!

  5. Weyrleader
    September 23, 2013 at 5:26 pm

    @Abhishek - There is a link in the article which will tell you how to do this. Here's the URL from the article just in case you missed it: how to check if someone’s been using your PC

  6. Abhishek
    September 22, 2013 at 10:12 am

    "Makeuseof" is an ultimate website. It provide new information everyday.
    I am using Windows 7. Is there any software or a way to find out who had used my PC in the last couple of day and actually what files had been accessed .

    • mike
      September 22, 2013 at 2:33 pm

      Call the NSA. They can tell you.

    • Justin P
      September 23, 2013 at 3:39 pm

      Hey there. This Mac article is actually a follow-up to a similar PC one, which you can read here:


      It won't do exactly what you're looking for, but with a little detective work you should be able to deduce who used your computer and which files they looked at.

  7. Miller
    September 21, 2013 at 8:49 pm

    I work IT and I don't know anyone who uses a Mac.

    • Justin P
      September 22, 2013 at 12:50 am

      Where do you live, I wonder? Because here in Boulder you can't throw a stick without hitting five...

    • Jon Heil
      September 22, 2013 at 8:40 pm

      Ha.. Yup or people who don't know how to use real programs or just graphic designers.. but then again the caption should be "Only Pussy(cats)'s use a Crapple!"

    • Sassy Lou
      February 18, 2015 at 9:14 pm

      We work in midtown Manhattan...we can't even find a PC user to test video files on!!!!
      I think the only people using PC are corporate drones. We can only find them in headquarters in certain offices.

      Da PC is gone from the rest of the civilized non corporate world!!!!

    • Justin Pot
      February 18, 2015 at 9:55 pm

      Midtown Manhattan is pretty different than the rest of America, and the planet. What you see there doesn't reflect most people's experience, believe.

      Written from Boulder, another bubble of prosperity riddled with Macs.