How can I recover data from an overwritten disk?

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						I started cloning my computer to an external drive which contained several files and archives with Macrium Reflect (free version).
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						It was my first time using Macrium. I normally always used Windows 10 built-in backup, which I stored in the aforementioned external drive.
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						So I got a prompt telling me that the drive would be overwritten and I don't know what my brain was doing that I just accepted it and clicked "continue". As soon as cloning started, I cancelled it. But now the drive is no longer accessible and softwares (e.g. Dropbox) that were installed in this hard drive are now unaccessible.
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						The external drive does not have any previous versions available.
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						Is there any chance I can recover about +400GB of files from the external drive?
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						Desperate please and thanks
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You might be better asking over at Macrium, it's their software that you were using: https://forum.macrium.com/