This feature is available in the Folder Tools sidebar for paid users.
Options:
Folder ID – add the id of folder to search for duplicates
Find Duplicates – click to find the duplicate files
Delete Marked Duplicates – click to delete the files that have the delete action in the F column
How to use
Step 1
Add the folder ID of the Google Drive folder you want to find duplicates in.
Step 2
Click Find Duplicates and wait for the process to finish, depending on the number of files in the folder it might take a few seconds. Sometimes this process might timeout due to the limitations of your type of Google account.
The sheet will be populated with the files that are duplicated. In the F column you will see the Action delete on the duplicate file(s) found. If you don’t want to delete certain files please remove the delete action for that file.
Step 3
Click Delete Marked Duplicates and confirm with yes. The deletion process will start and you will receive a confirmation message when the files are deleted.
If you have a folder with thousands of files and you are sure there are more duplicate files, start again with Step 2.