Dropbox installation on new laptop is a complete disaster. All my files ended up taking up space.

Hi Megan,

I just wanted to let you know that I managed to resolve the problem, at last. I did get the external drive first and saved everything (which took several days), and then I double-checked that the Dropbox app was uninstalled and made sure that the laptop was disconnected from my Dropbox online. Then I deleted the Dropbox folder on the laptop, and afterwards I started the Dropbox app installation again.

In the meantime I'd found an old thread somewhere, where actually several people had similar issues to mine, not being able to stop Dropbox from filling up their hard drives, quite inexplicably. It's a very small minority of Dropbox users who are affected by this, and it was suggested there that this may happen when a third party overrides the default Dropbox installation, such as an antivirus program, firewall, or some organization. The latter applies to me, as I don't have full admin rights on my computer which is owned by my university. Of course my university claims that this has nothing to do with how Dropbox acted on my laptop, but I'm convinced that all my troubles are actually due to the fact they they've managed to create some settings on my laptop (unintentionally) which resulted in overriding the default settings and installation procedure for the Dropbox app.

So, the procedure that worked for me under these circumstances was the following: after installing the Dropbox app, I deselected all my folders on my laptop in selective sync first and let that sync (or, actually, not sync...) for about a day. Then I made sure that the "Save hard drive space automatically" was on in my Dropbox Preferences, and subsequently selected my folders to make them visible again in selective sync, ensuring that all of them were set to online only. This sequence did the trick. I believe that the key step that I was missing before was to immediately de-select all the Dropbox folders in selective sync after installing the app, which actually stopped Dropbox from syncing all the files to the hard drive, unlike simply selecting the online-only option from the beginnig which did not make any difference and never worked. Afterwards I was able to re-introduce these folders in the online-only mode, which was not possible before.

I hope that this solution will be useful for others who have similar troubles to mine , which makes computers with small hard drives unusable.

Also, thanks for your help! I appreciate it.