Can you just clarify, does the app appear to crash and restart, or is it just in a continuous state of "Starting"? If it's crashing you should see the icon disappearing and reappearing in your system tray.
Also, can you let me know which version of the app you have installed? You should be able to see this by hovering over the Dropbox icon.
Please feel free to send along any screenshots too, excluding any personal info.
I am using Windows 10 Home, 64 bit, version 20.04, build 19041.508 and Dropbox 105.4.651 .
Dropbox seems to be in a continous state of starting, first it displays (original text from german version) "Verbindungsaufbau" (establishing connection) and then "Warten auf Verknüpfung mit einem Dropbox-Konto" (waiting to be linked to a Dropbox account".
When left-clicking on the Dropbox icon for accessing the settings, the "box" animation runs forever, at least for 90 minutes yesterday.
On my other user account on the same computer, running the same Dropbox version, the expected screen is displayed within some moments.
Possible reasons for such a headache could be broken web query assignment (default browser set) or broken application instance configuration.
What's going on when you try open a HTML file residing on your computer locally (doesn't matter what exactly, just something), while you are logged in using the same local user? Does the correct application open (i.e. the same browser you have used to log in)? If not, correct it.
You can fix possible broken configuration using represented here. Use the actual path according your user to navigate to! Actual reason could be the same (or similar, at least).
Edge and Chrome refuse to start for that user. A W10 error message appears saying that no app is linked to this action when clicking on a https link received in a mail. I try to investigate on this. It seems that the primary problem is Windows related and not Dropbox related. Unfortunately the referenced problem does not contain a solution for my case.
... Edge and Chrome refuse to start for that user. A W10 error message appears saying that no app is linked to this action when clicking on a https link received in a mail. ...
Get in your favorite web browser, either Edge, Chrome, or might be Firefox, for example. Navigate to the browser settings. Somewhere in have to be something like "Set as default browser" (exact text could vary). Currently seems you haven't assigned such. Hopfully this should fix openning web files.
@JeanRM wrote: ... Unfortunately the referenced problem does not contain a solution for my case.
Are you sure? 🤔 Did you check or just suppose? The problem there is different, definitely, but the reason could be similar - broken configuration!
Add: Sorry! I just take a look there and seems the path where you should navigate to got erased. Somebody has gone too far, I think. Anyway... You should navigate to "C:\Users\<User>\AppData\Local" (set the corect user directory) and remove "Dropbox" directory residing there. 😉