There is an extensive tutorial here from the guys at MakeUseOf. I shall write it here though:
- Open the Terminal (again)
- Type (or just copy and paste) this command:
Hit enter and insert the next command line:
$ HOME=$HOME/.dropbox-alt /Applications/Dropbox.app/Contents/MacOS/Dropbox &
It should now look like:
- A new Dropbox icon will appear in the menubar.
- A Dropbox account setup window will also pop up. Follow the setup
- At the last setup step, tick the option to choose your own location of Dropbox folder. Hit the “Change” button to determine the location.
- After the setup process complete, you can close the terminal. Theoretically, the extra Dropbox instances will also be closed, but in my experiment it remained in the menubar.
If you wish to add it as a startup item, the tutorial also shows that.