Caja Dropbox does not open

Hi! I am running Ubuntu Mate 18.04 and now have a problem with Caja Dropbox: it no longer opens!

I have tried the command line ¨caja-dropbox start -i¨ and always get "Dropbox is already running!¨

Suggestions on how to repair this?

Please try solutions given in similar thread.

Is it clean installation or upgrade from 16.04 LTS?

Thanks. It was a clean install.

Thank you. I uninstalled and then installed again Caja Dropbox. That did the trick: Dropbox now works fine.