Cisdem Duplicate Finder Review

I’ve been a lover of productivity tools for a long time. When I saw that Cisdem Duplicate Finder was available on the Mac App Store, it caught my eye. I have to admit it; my Mac has been stuffed with duplicate items (identical photos, redundant backups, etc.) ever since I started to use the machine to sync files on my iPhone and iPad.

In this Cisdem Duplicate Finder review, I’ll walk you through the app and see how it works to detect and remove duplicates on Mac. I’m also sharing its pros, cons, and my personal takes.

Note: the app isn’t freeware, it costs $29.99 to buy a license that allows you to access all full features.

Quick Summary

Cisdem Duplicate Finder is an intelligent Mac cleaner app that can help you save a lot of storage space on your Mac or external drives. It’s lightweight and convenient to use.

Within a few clicks, you could free up gigabytes of disk space. However, it is not for all Mac users, especially those of you who have a new Mac or external drive and don’t backup/transfer files heavily.

But if your Mac (or external drive) is running out of storage space, Cisdem Duplicate Finder is as good as it claims to deal with duplicate files and I can’t recommend it enough.


  • It can help you free up a significant amount of storage space on your Mac or external hard drive.
  • It’s smart and precise in the automatic selection of duplicate files, time-saving.
  • Incredibly easy to use with well-designed interfaces.


  • Lack of warnings while users take major actions, for example when hitting the “Delete” button.
  • It does not allow you to deselect specific folders before the scan.

Is Cisdem Duplicate Finder Safe?

First of all, the app is notarized by Apple as you can see from the Mac App Store, this should give you peace of mind.

From a security perspective, the app is safe to download and use. Malwarebytes Antivirus software didn’t report any issues once I ran a thorough scan of my Mac after installing the Cisdem app.

From an app design perspective, the app is also safe to operate. After scanning a folder to find duplicate files, Cisdem Duplicate Finder removes the files to Trash upon your request. That means, if you realize you made a wrong action, you can always undo it by checking Mac Trash and pulling those files back.

Therefore, it’s safe to say Cisdem Duplicate Finder is well-designed and does not contain any virus/malware; thus it’s 100% safe to use.

Cisdem Duplicate Finder: Detailed Review

Installing the app on Mac is pretty easy and straightforward. Launch the app and you’ll see its main screen like this.

The big blue arrow down icon in the middle means you can drag and drop any folders to scan. Alternatively, you can click the “+” button on the left to do the same. Once you select folders that might include duplicate files, the blue “Scan” button on the right becomes clickable. You then hit it to continue.

Cisdem supports detecting duplicate files that exist in both internal Mac hard drives and external drives. I’m here to break down the features into two scenarios — one is to test its capability to locate duplicates on my Mac hard drive (SSD-based), and the other is to do that on an external storage device (Lexar flash drive).

Scenario 1: Finding Duplicate Files On a Mac

Step 1: I clicked on the “+” button, and it brings me to a new window, asking me to select the folders (for scanning). I’m pretty sure I have tons of duplicates in Documents. I chose that folder and clicked “Open” to get started.

Step 2: The app showed I had selected one folder, I then clicked the “Scan” button to continue.

Step 3: The scanning process began. In a few minutes, it scanned 49,916 files, and found 15,987 duplicates totaling 4.56 GB — that means 30% of files in the Documents folder are duplicates. That’s kind of unbelievable.

Step 4: A further review revealed that many of the duplicates were videos and archives (backup files) that I saved.

Scenario 2: Finding Duplicates on an External Drive

Preparation: since I barely use my Lexar USB flash drive for backup purposes, there weren’t many duplicate files on the disk. I thus copied a batch of documents and images from my Mac and saved them to the Lexar USB drive.

Step 1: Likewise, I first launched the app and clicked on the “+” button to add folders. In the new window, I selected my Lexar drive under “Devices.”

Step 2: I clicked the blue “Scan’ button to continue.

Step 3: The scanning kicked in, in my case, the process took less than a minute to complete. The result? 747 files scanned, 626 duplicates with 94.1 MB in size found.

Step 4: A quick overview showed that they were documents and images that I had saved previously. Excellent job!

Removing Duplicate Files

After the scan is complete, you can view the duplicate files via the tree-style panel on the left. Just select a file, and it’ll show you how many duplicates it has. The part that I especially appreciate is the automatic selection feature — meaning all duplicates are auto-checked, and all you need to do is hit the “Delete” button to get rid of them.

Pro tip: I highly recommend that take extra time to review these files before hitting the button. This is critical because you may not want to remove some duplicates as they serve as additional backups that are meant to keep.

Also, the part I feel that the Cisdem team could improve: when I clicked “Select All” or “Delete,” there weren’t any warnings or alerts popping up indicating the actions could be irreversible. Because when I hit the “Delete” button to erase duplicates on my Lexar drive, the files were removed immediately without going to Trash.

Speaking of this, here also comes a difference when removing duplicate files from a Mac versus doing so on an external drive. Unlike external drives, when you delete duplicates on your Mac, those files will be sent to Trash by default (unless you change the Removal Method in Preferences, see below for more). To fully claim the storage they occupy, you’ll have to take one more step — i.e. emptying Trash. It’s a bit tricky because Cisdem does not give users any hints.

App Settings

Here’s the part I highly recommend you take a look at before using the app.

On the main interface of the app, locate the gear icon in the upper right corner. Click on it, and you’ll see this Preferences window.

Under the General tab, you have the option to choose the “Scan Method” and “Removal Method.” By default, the app scans folders by file content and removes found duplicates to Trash. You can adjust them accordingly but do this with caution.

Under the Filters tab, you can select file size range to scan or skip files with particular extensions. I find this very helpful.

For example, if you only want to find duplicate files that are larger than 50 MB, you then move the bar from “0 KB” to “50.00 MB”. Likewise, if you have some backup files in .zip folders, click the “+” sign and add the archive file type into the filter box.

The “Issues”

Although Cidem Duplicate Finder is a nice app, it’s lightweight and incredibly easy to use; there are several things I personally feel the developer team could have improved.

First, the app doesn’t allow you to deselect folders. For example, when I select four folders on my Mac to scan (see the screenshot below), and later I decide only to scan two folders — meaning I need to remove the other two.

On the app, I click on the red “-” icon, and to my surprise, all four folders are removed. It would be nice if Cisdem allows me to remove the folders I specifically don’t want to include, instead of removing all the folders I selected previously.

Second, there are no warnings before I take major actions that might be done by accident. For example, when I was reviewing files, and I clicked the “Select All” option, it would be good to see a friendly popup indicating I had selected multiple files and a further review might need before hitting the blue “Delete” button.

Likewise, a warning would show up when users click on the “Delete” button, because if the duplicate files are on an external drive, they would have gone for good rather than being sent to Trash.

Last but not least, these days pictures and videos tend to take up most of the storage space on our Macs, and the chances are we’ve got multiple copies in particular places like ~/(username)/Pictures, Mail attachment folders, etc.

Therefore, if Cisdem could give users directions to select these folders, very likely it’ll harvest more duplicate items without wasting time scanning other unnecessary folders.


Is Cisdem Duplicate Finder Free?

The app is free to download and try, but it isn’t freeware. More specifically, the trial version allows you to scan folders and find duplicate files, but you can’t remove the duplicate items. When you attempt to do so, a new window (like this) will pop up asking you to register the program with a key.

How To Get Cisdem Duplicate Finder Key Code?

You’ll have to purchase the app by clicking the buy button or visiting the official Cisdem store. Select the type of license, based on the number of Mac machines you want to use the app. A single License starts at $29.99 USD.

Once you purchase it, an activation key code will be sent to you by email instantly. You then copy the key and activate the app to unlock the removal feature and permanently clean the duplicates.

Pricing and Compatibility

Cisdem Duplicate Finder requires an Intel-based Mac with at least 512 MB in physical RAM, and OS X 10.8 Mountain Lion or later. The app is localized in English and French.

Price starts with a one-time fee of $29.99 per Mac. Approved schools, organizations, churches, and government entities may enjoy up to 20% discount.

How to Uninstall Cisdem Duplicate Finder On Mac?

The app is lightweight and pretty easy to uninstall. To do so, simply select the app icon and drag it to Trash. See this screenshot.

Final Verdict

Cisdem Duplicate Finder works great to detect unnecessary duplicates with its smart features and algorithms. If you are looking for an app to help trim the fat and clean the cruft that has accumulated on your Mac machine or external hard drives, this is it.

But if you are using a relatively new Mac with plenty of available storage space, you probably don’t need it. Bottom line — it is an excellent productivity tool for most Mac users.

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  • Ed

    Great review. Thanks for the detailed information.

  • Marie

    Also I have a question I am not young so some of these questions may seem silly. I downloaded this software but it shows up on my screen as an external thing. How do I get rid of that and where do I put it. When I click on what looks like an icon on my desktop as a external drive or something then a window comes up with the little picture of the cisdem duplcate finder in it. I don’t think I did something right. I need help thanks.

  • Marie

    I have a new iMac 2017 and when I click on photos it doesn’t go through my photos at all what am I doing wrong

  • Doug

    Why can’t it access the All Photos tab in Photos
    That’s where my duplicates are for the most part

  • John M

    It won’t delete the duplicates from my hard drive, either. It scans, locates, and even shows how many GBs it can free up, then it appears that it is deleting the files. But the hard drive still shows the same amount of free space after it is all done. Then I run the scan again, and it finds all of the same duplicates again. I have a Seagate 640 GB external hard drive. Any thoughts?

  • Keith T

    Is there a reason why it won’t delete duplicates on my external drive?

    • Avatar photo

      What’s the specific model of your external drive? Also, Is it password-protected?