I've installed Dropbox on my new laptop (Windows 10) with a 235GB hard drive and I've chosen online-only at the installation. Nonetheless, Dropbox has filled my hard drive and made my laptop completely unusable. I've checked all my folders for online-only, and there was one which was not set to online-only, the rest were. I've tried several times to set the last folder to online-only but I didn't succeed, since it still kept showing the option of online-only. I have no idea why that one folder was not set to online-only, and also that one folder by itself was not big enough to fill my hard drive. I couldn't see any solution to this puzzle, but since I desperately needed a solution, as I couldn't download even one file to my laptop due to a completely full hard drive, I set all my Dropbox folders in selective sync to not show on the laptop. That didn't make any difference to my hard drive either, it's still completely full. In fact, very annoyingly, I kept getting notifications from Dropbox asking me to free up some space, since it cannot sync files. Of course there was nothing that I could free up (it's a brand new laptop, so I don't even have temp files), as the space was taken up by Dropbox...
As my next desperate act, I uninstalled Dropbox from my laptop, and now I have the following weird situation. In file view, I see only one file in Dropbox, which was somehow outside of all the folders, so it is showing there, unlike all the folders which I deselected in selective sync. This is a 300KB file. However, when I look at my Dropbox folder in storage, it shows that Dropbox is occupying 73GB! (apparently the rest of the 235GB is taken up by system files, and 102GB is needed for system restore). This is a completely bizarre situation. Now you will probably tell me to go ahead and delete the Dropbox folder on my laptop, and this may (or may not) free up my 73GB hard disk space. However, at this point I am really paranoid about anything related to Dropbox, since so far nothing has worked the way it is supposed to, and it's driving me crazy that everything I find on the internet says that smart sync (online-only) and selective sync should work - well, they didn't work for me, quite the opposite, Dropbox has completely destroyed my laptop (so far)...
So, even though I have uninstalled Dropbox, I don't trust anything about Dropbox, and I am nervous about deleting the Dropbox folder on my laptop, as I don't want to lose my files in Dropbox. I cannot even do a partial delete to test the situation, as I don't see any folders under Dropbox (due the deselecting all folders in selective sync). I've tried to delete the one remaining file under Dropbox on my laptop to test whether that would change anything in my Dropbox online, but I received an error message. The error message says that "an unexpected error is keeping you from deleting the file." At this point this is not so unexpected... everything is going wrong, and this whole situation is very confusing. Can anyone tell me what's going on? Can anyone hep me out and tell me what to do? And most importantly, can anyone reassure me that whatever happens on this laptop, it won't make me lose my files from Dropbox? I would really appreciate it.