FTP message

Sometimes when I upload files with my ftp client it spins for a while with the message “Compute md5 hash…”.
If I stop it, it stops doing what its doing and uploads the file.
Does anyone know what is happening during this process?

Thank you!

What FTP program are you using? My guess is it is cycling through all of the files on the server and locally and computing the md5 hash for them, so as you drag and drop files, it can quickly identify if the files are the same or if they are different and should be uploaded.

I’m using CyberDuck. That makes sense. I always wondered what that meant.