Try DRS Outlook Duplicates Remover Tool. This is the best tool for removing duplicate email in an email account. Because duplicate emails obtain unnecessary space in your email account. So, you should remove these duplicate email files in your email account.

It's been about six years since this was first suggested, is there any update on this? I agree that this would be a useful feature. One use case would be some of the files that get randomly downloaded on my phone and maybe copied/moved to other folders. Another would be files that I have setup to automatically get downloaded daily to Google Drive but are occasionally the same between two days. Additionally, I would want the duplicate detection to be fairly "smart" with the option to detect duplicates based on CRC checksums or something that otherwise compares actual contents (and not just same filenames or file sizes).

Is there any hope for getting this support built-in, or should I be looking for something else to serve this particular purpose? Just wondering if waiting will pay off or not.

It might help out the project considerably to implement a duplicate file detection algorithm already used in open source and well-documented apps, like this one:
https://www.codeproject.com/Articles/1106099/Yet-Another-Duplicate-File-Detector-MVVM-Pattern

I need this, especially with support for cloud storage.

This is something every file manager must have.

i need this feature, please, especially for google drive

I would absolutely love this feature. Especially if the cloud was supported. Would be very handy.