Step 5

Step 5: Checking files

Common information

To tell DoubleKiller which files you want to remove, you have to check them in the result list by clicking their file icons (). A cross will appear, indicating it is marked for removal (). Apart from checking the files manually, you can use the buttons to the left of the result list. They offer various ways of checking a bunch of files at once.
For more information on checking files manually, especially using keyboard shortcuts, see Check files, but please read the section below first. On this page's bottom you will find two examples of checking files automatically.
Note: You can start checking files even while the scan is still running.

Hint: Which files may I delete?

If you did not scan a folder just to find certain duplicate files you were aware of, but instead wanted to clean up your hard disk, the worst idea is to carelessly use the check first files of group button and delete the files - this way you will most probably delete one or more files you should rather keep. This is especially the case if you were not following the suggestions in Step 2 and scanned something else than your personal file collections.
The safest way not to delete the wrong files is to check the files manually and only check the files you know - do not check any file of which you are not perfectly sure if it is used by Windows or some software. To be on the safe side, do not delete any files that you cannot open e.g. in your image viewer or multimedia player, because it might contain data belonging to some application. If you are quite sure such a file is not needed anymore, e.g. because you think it belongs to an application that has already been deinstalled, you can try moving it to Windows' Recycle Bin or a backup folder and just continue working on your PC for some weeks to make sure everything is running fine before finally deleting it.

Example 1: Check all files within a folder

In our example we scanned all MP3 files in 'G:\Mp3 & Ogg' and 'F:\Sounds'. Let's assume we now want to delete all duplicate MP3 files of 'F:\Sounds' because they are supposed to be in 'G:\Mp3 & Ogg' and nowhere else. You could now run through the list and manually check all files that are in 'F:\Sounds' or its subdirectories. But fortunately, there is a feature designed to do exactly that (and something more): Try the button by criteria... to the left of the result list.

This will bring up a dialog titled check / uncheck by criteria. The only thing you need to do here is checking path matches mask and entering F:\Sounds\* in the box below.

Click OK and all files located in 'F:\Sounds' and its subdirectories are checked automatically.

Example 2: Check the oldest files of each set

Note: If you were already trying the example above, make sure to remove the checked files to tidy up the result list before following this example as well. Otherwise you might end up with duplicate sets that are completely checked and you will have to manually uncheck files.
Checking the oldest files of each set can be automated very easily. Firstly you have to make sure the oldest files of each set appear first. To do so, simply sort the result list by date by clicking the Date column header.

Now that the results are sorted properly, you can use the check first files of group button to check all but the very last file of each set.

Because of the sorting, this equals to checking all but the newest file of each set.

See also
Check files