Hey Matman, thanks for posting us your security-related concern on our Forum, let me send you some information & we’ll take it from there.
#1. If so, I need to know, where on my Windows PC, Dropbox moves 'copies' of my files / folders to, because I want to check if those 'copies' remain in a Dropbox Folder on my PC, 'after' Upload to Dropbox's Cloud Storage
For starters, please note that Dropbox settings are stored in an encrypted database file and cannot be accessed or changed outside of the Dropbox client.
Following, it would be worth mentioning that Dropbox keeps a cache of files for efficiency and emergency purposes. It is also used as a staging area for downloading and uploading files.
If you need to delete sensitive files immediately, or you need to clear up some space on your hard drive, you can manually clear the cache.
#2. If a Hacker / Attacker gained access to my PC and delved into my C: Drive, could they locate a Dropbox 'Program' Folder into which Dropbox had earlier placed 'copies' of my Files / Folders,
In the unfortunate event that an attacker gains access to your device, their visibility will merely depend on the security measures you’ve already implemented on your pc/ Mac up until that point in time, therefore in case you’d like to add an extra layer of security, you could apply some common-sense security habits (i.e. changing your password often &c.).
#3. Can Dropbox be configured in such a way that it only uploads files / folders from my 'Portable' Hard Drive, and does not attempt to upload anything from my C: / Other Drives?
Have you moved the Dropbox folder to your removable drive by any chance? While you can move the Dropbox folder, we recommend proceeding with caution. Whereas it is currently an option, if the external drive is disconnected from the computer while Dropbox is running, there's a small—but real—chance that the app will start deleting files before realizing that the entire drive has been removed.
Hopefully my reply addresses your concerns & please do let me know on this discussion in case you’d like me to clarify any of the above. Thanks again for reaching out to us & I'm wishing you a wonderful weekend ahead!
