I have been uploading a 70GB folder from my laptop, for few days the laptop has been uploading almost 50% of the folder, at the end it stopped working and now I'm not sure how much of the upload has been done and what is missing. How can I check the number of file and folders, what happens if I upload again the folder? Does it merges the files avoiding duplications?
If you're uploading through the website, the upload will start over again from the beginning. The website was not meant to handle uploads of that size. You should be using the Dropbox client and allow it to sync the files automatically. If a sync process is interrupted with the Dropbox client, it will automatically resume when it reconnects.