Identical, duplicate files are uploaded unnecessarily

[Eldaw]

I did a test with the Backup feature in v5.5.0 of the MEGAsync Windows client. I created 2 separate Backups, each one pointing to a different local folder, however each local folder contained an identical set of files.

After the first backup had completed, I expected that when I added the second backup (pointing to an identical set of files), the MEGAsync client (working together with the MEGA servers) would identify that each file was already present in my MEGA account, and would not have to upload the full contents again. But instead, every single file was uploaded a second time, taking just as long as the first backup.

Considering that the MEGAsync client hashes files locally, and has full access to my MEGA account on the server (where the hashes are also known), I was expecting some intelligence to be applied in the backup process. Surely the MEGAsync client should be able to avoid uploading files which it can see already exist in my online account. The current way it works, where duplicate files are uploaded again, is very wasteful and time consuming.

[perigozin]

I was about to create an issue for something similar. I have a folder with over 200GB of files that was already synced (using the backup option). Yesterday I renamed it from "Production" to "Audio" and now MEGA is uploading the files all over again. This is the second time it happens this week and from what I remember this was not an issue before (been using MEGA for years).

The worst part is the original folder that was renamed still exists when I access my MEGA account from a browser, so it takes twice as much space and I have to delete it manually.

Now I feel a little apprehensive renaming things because it might reupload duplicates or mess up with my files in the cloud.