If your Mac starts to run slowly, the first thing to check is that you are low on space. It is generally recommended that you have 10% free space on your Mac for the most optimal experience. If you’ve got the last few GB left, then it’s time to do some household chores and reclaim some space.

Over time, a Mac can accumulate a large collection of duplicate files that take up this valuable space, so this is a good place to start. However, finding and removing them can take a long time if you do it one at a time, so in this article, we will show you faster ways to clean your system of these illegal twins.

Why do I have duplicate files?

Most of the time it will be erroneous downloads (caused by double-clicking a link), attachments in Mail and Messages, a confusing file system, the bad habit of dragging things onto the desktop, or a number of other possibilities. Unless you’re an unusually picky Mac user, duplicates will show up one way or another.

How to Find Duplicates with Finder

You can find duplicate files on your system using Finder’s Smart Folders feature.

1. Start by opening the Finder app.
2. Go to File > New Smart Folder.
3. Click on the “+” button in the upper right corner.

Now you can search for documents, photos, music, or several other types of files. The key is how you sort the results. Ordering them by name should reveal any easy-to-find duplicates. (If it doesn’t appear in name order, click the drop-down menu to switch to list view).

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Just be sure to check the date to make sure it’s a real duplicate – for example, you don’t want to delete the wrong version of an important document. (If you don’t see the date, right-click and select Date Added, you can even add the last opened date to make sure you’ve selected the correct date to delete.

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While this is doable, it is far from ideal. One problem might be that you gave the same file different names and this method won’t show it.

It’s also a time-consuming process, and the time spent poring over a long list of files could be better spent visiting the App Store and purchasing software that will instead find and safely remove duplicates.

Best Apps to Find Duplicate Files on Mac

The Mac App Store has several duplicate file finders that will automatically search your system and recommend duplicate files that can be removed.

Many of them are free, including Duplicate File Finder Remover and Duplicates Cleaner. You can also try the Find Duplicates feature in Parallels Toolbox, which offers a seven-day free trial, and we like MacPaw’s Gemini 2, which has a three-day trial.

Most apps offer similar functionality: you ask the app to scan your hard drive, and then you’re presented with a list of duplicates, accompanied by the original file, so you know which ones are safe to remove.

All of the apps listed above will certainly clear up space on your Mac, and you can always start with the free ones and then upgrade to the paid version later if you find the features useful.

Usually you will have to upgrade to the paid version for advanced features like removing duplicate folders, hidden files and similar features.

Gemini 2

Gemini 2: The Duplicate Finder is one of our favorite duplicate remover apps and has received good reviews from customers. It is free to download and includes a free 3-day trial. It offers the Smart Cleanup feature for $19.99 / £18.49 as an in-app purchase. While the title might be more in line with a dystopian sci-fi novel, the app is a powerful tool for your Mac.

Once you give permission to scan your folders, Gemini 2 will start scanning for duplicates. Scanning our 256 GB drive (with files around 150 GB) took about seven minutes. When the scan finished, 12.63 GB of duplicates were found.

Gemini 2 automatically selected 45.6 MB files – these were duplicate photos. We were able to automatically remove them by clicking Smart Cleanup.

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However, there were still gigabytes of files left to delete. You can sort duplicates by choosing which version to keep. Click “Select More” to see all the duplicates Gemini has found. You can scroll through them and choose the one you want to lose. It’s a little tedious that you have to do it manually, but it’s still easier and more visual than using the Finder. You can also delete each instance of a file or photo if you really don’t need it.

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Since we were deleting photos, Gemini reminded us that we also need to remove photos from the Recently Deleted in Photos list, alternatively we can wait 30 days for them to be deleted automatically. You can review what has been deleted and “revert” any files you have doubts about (but this step must be completed before you delete the contents of the Recently Deleted folder).

Gemini can not only find duplicates of any files on your hard drive, but also search external drives and cloud storages such as Google Drive and Dropbox. All this is accompanied by the ability to immediately replace any accidentally deleted files.

Learn more about Gemini and other related apps from the firm, such as CleanMyMac X, on the MacPaw website.

Search for duplicate files

Duplicate File Finder can scan your home folder, or you can select a specific folder or drag and drop files into it. There are two versions of the software – free and Pro version. The latter adds a few extra features such as the ability to merge folders and recover deleted duplicates. The Pro version costs $19.99 / £20.99 for a single Mac.

You will need to give it permission to scan various folders and partitions on your Mac. The software will then scan for duplicates with some fancy graphs representing the types of files it finds.

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You can then click on the “Cleanup Tips” section to find the files to delete. Each step has a detailed overlay showing what to do. Just click on the x to remove it.

In each case, you can preview the duplicate before deleting it. As with Gemini, you can remove duplicates or remove all versions of a file or photo. The View and Delete option lets you see where the duplicated file is, which can be helpful.

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You can also select “Auto Select” to select duplicates for you – you can even refine your selection. You can review them before they are removed.

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Duplicate File Finder creates a Duplicates album in Photos, which you will need to delete in the Photo app. You will also have to remove them from Recently Deleted.

More advice…

For more clutter tips, be sure to read our How to Free Up Space on Mac feature and a separate article that explains how to empty Trash on your Mac. We also have tips on how to remove duplicate music in iTunes (or the Music app).

We also have this guide on how to speed up a slow Mac and how to delete other storage on Mac, how to delete system on Mac and also an article that explains how to delete cache on Mac.