In my experience this won't do the right thing, at least if you only want Dropbox to run during user sessions (without enabling linger, which keeps your systemd user session running even before and after you log out).
If you do want dropbox to run only at login, and be terminated upon logout, better to use this unit file:
[Unit]
Description=Dropbox Network Storage Daemon
After=graphical-session.target
[Service]
Type=forking
PIDFile=%h/.dropbox/dropbox.pid
ExecStart=/usr/bin/dropbox start
ExecStop=/usr/bin/dropbox stop
[Install]
WantedBy=default.target
The important change is to give it the location of dropbox's PIDFile= within your home directory, so that systemd can monitor the true dropbox process (${HOME}/.dropbox-dist/dropbox-lnx.x86_64-49.3.66/dropbox_py3 on my system, currently) while it's running, as well as confirm that it's correctly responded to start/stop commands.
Also, After=graphical-session.target ensures that it will only be started after Gnome Shell is running.
With this unit file installed and enabled, and dropbox.service started, systemd properly monitors the process and can manage it correctly:
$ systemctl --user --full --no-pager status dropbox.service
● dropbox.service - Dropbox Network Storage Daemon
Loaded: loaded (XXXXXXXX/dropbox.service; enabled; vendor preset: enabled)
Active: active (running) since Thu 2018-05-03 21:35:41 EDT; 9min ago
Process: 14805 ExecStart=/usr/bin/dropbox start (code=exited, status=0/SUCCESS)
Main PID: 14889 (dropbox_py3)
CGroup: /user.slice/user-1000.slice/user@1000.service/dropbox.service
└─14889 /home/XXXXXXX/.dropbox-dist/dropbox-lnx.x86_64-49.3.66/dropbox_py3 /py3 /newerversion
May 03 21:35:41 HOSTNAME dropbox[14805]: dropbox: setting program path '/home/XXXXXXX/.dropbox-dist/dropbox-lnx.x86_64-49.3.66/dropbox_py3'
May 03 21:35:41 HOSTNAME dropbox[14805]: dropbox: setting home path '/home/XXXXXXX/.dropbox-dist/dropbox-lnx.x86_64-49.3.66'
May 03 21:35:41 HOSTNAME dropbox[14805]: dropbox: setting python path '/home/XXXXXXX/.dropbox-dist/dropbox-lnx.x86_64-49.3.66:/home/XXXXXXX/.dropbox-dist/dropbox-lnx.x86_64-49.3.66/python-packages-35.zip'
May 03 21:35:41 HOSTNAME dropbox[14805]: dropbox: python initialized
May 03 21:35:41 HOSTNAME dropbox[14805]: dropbox: running dropbox
May 03 21:35:41 HOSTNAME dropbox[14805]: dropbox: setting args
May 03 21:35:41 HOSTNAME dropbox[14805]: dropbox: applying overrides
May 03 21:35:41 HOSTNAME dropbox[14805]: dropbox: running main script
May 03 21:35:41 HOSTNAME dropbox[14805]: Done!
May 03 21:35:41 HOSTNAME systemd[1690]: Started Dropbox Network Storage Daemon.
Is it possible, that after starting
/usr/local/bin/dropboxd, the daemon detaches? If yes, try to make it not detach (see--helpor man page). If you cannot stop the daemon from detaching, try changing theType=option, e.g. toforking. Seeman systemd.servicefor details.thanks - it wasn't the type but rather the initial configuration and target. Check my answer.