I think I've found a workaround for this problem (I'm on Linux Mint 17.3 Cinnamon 64 bit flavour).
I had created a new entry in Startup Application settings to replicate the launch of Dropbox service and I deleted the original Dropbox entry. But, after a reboot, I have 2 Dropobox entry in Startup Applications.
It seems that Dropbox service makes a copy of the "dropbox.desktop" file from /usr/share/applications into ~/.config/autostart, so rewriting any changes made into the latter copy of the file.
So I've modified the original one file /usr/share/applications/dropbox.desktop file adding the following line at the end of the file itself:
Code: Select all
For now, after several reboots and logins, it seems it's functioning.