Anti-Twin is a Windows application which is one of the best tools for identifying and removing duplicate files. It is free for personal use. The duplicate removal step is very tedious in most duplicate file finders but this is not the case in Anti-Twin. The features available in Anti-Twin are not exactly unique but the user interface makes it really easy to use. One caveat is that Anti-Twin has not been updated in many years. However, that shouldn’t be a problem as their website lists it as being compatible with Windows 10 and it has been working fine for me in Windows 10.
You may have to run Anti-Twin as administrator depending on which folder you are trying to remove duplicates from. For example, you may need administrative privilages if you are trying to remove duplicates from a removable drive.
Anti-Twin has a two tab layout with a Start Search tab and a Result tab.
Search for Duplicates
Choosing a folder to scan
Select the folder you want to scan, using the button to the right of the Basic folder label. You have to be careful about which folder you select. The scan must be restricted to folders containing your personal files or files which you know are safe to delete. The scan must not include system folders like Windows, Program Files, etc. For example, it would be a very bad idea to scan your entire system drive and remove the duplicates you find.
Adding a second folder to the scan
Anti-Twin also has the option of adding a second folder to the scan. This option is very useful if you want to find duplicates of files you have already archived in something like a DVD. Set the folder from the DVD as one of the folders to scan and the folder from Hard disk as the other folder. After the duplicates are found you can delete all the duplicates from the folder on the Hard disk with just a few clicks.
Anti-Twin supports filters like searching only for files within a specified size range, files with specified extensions, etc.
As far as comparison methods as concerned, the main options are Compare Names and Compare Content. Compare Names option is very fast but is also very risky. Use this option only if you are sure that in the set of files you are working with, duplicate names imply duplicate content.
Compare content is the default and the primary comparison method. The match min option might be useful for certain file types like mp3, image files, etc. For example, by adjusting the match min value you may be able to find mp3 files with the same audio content but different tag values. Remember that while reducing the match min value below 100% lets you catch more duplicates, it is also slower and riskier. You have to manually review files before deletion in this case.
The compare images option is specifically optimized for images. By combining this option with match min option you may be able to find similar images even if they are in a different format like JPG, BMP, PNG, etc.
You can also combine the Compare Names method with Compare Content method. This is faster than the Compare Content method without sacrificing on safety but has the obvious drawback that duplicates will be found only if both file names and file content match.
After you have selected the folder to scan and set the scan options, click the Search for duplicate files button. Anti-Twin will start searching for files and automatically activate the result tab. Here you can see your duplicate sets. Now you need to select the files you want to delete.
Marking files for deletion manually
You can mark files for deletion manually by clicking the small box before the file name. If the box turns red with a cross inside it, it means that that file has been marked for deletion. Double-clicking on the file name opens the file in its associated program. In case of image files, single clicking on the file name opens the file in a small preview window within Anti-Twin.
Marking files for deletion automatically
Anti-Twin’s real power is its ability to automatically mark files for deletion based on certain criteria. Click on the Selection by Folders button to open the Select deletable folders window.
Here you can mark one or more folders, whose duplicate contents would then be marked for deletion. In this example shown above, I have selected to mark all the duplicate files of the dupe subfolder for deletion. The Selection by folder option is very useful when you are doing the two folder scan mentioned earlier.
You can also mark files for deletion based on various properties of the file like date, name etc.
After you have marked all the files you want to delete, click the Delete selected files button. By default, Anti-Twin moves the marked files to a folder named antitwined in the root of the Drive. You also have the option to move files to the recycle bin or to delete them permanently. When choosing the move to recycle bin option, please remember that not all drives support the recycle bin.