Dropbox System Tray Icon Black Background

(Are you using nvidia drivers? from http://crunchbang.org/forums/viewtopic.php?id=38154&p=2, slightly updated)

This happens because nvidia driver overrode OpenGL library (libGL.so). This workaround works for me on kubuntu 14.04 [and linux mint 17].

1) close dropbox session

$ dropbox stop

2) find your nvidia system folder: in my systems it's /usr/lib/nvidia-331 (if you using another version of nvidia driver, for instance nvidia-340, your directory should be /usr/lib/nvidia-340). Take note of libGL.so.1 inside this folder

3) find dropbox system library. with dropbox 3.4.6 this is in the home directory.. the version number may change, and may have to be modified when you type it into the terminal

$ cd ~/.dropbox-dist/dropbox-lnx.x86_64-3.4.6/

4) backup your's dropbox OpenGL library:

$ mv libGL.so.1 libGL.so.1_backup

5) make symbolic link to nvidia's OpenGL library.:

$ ln -sf /usr/lib/nvidia-331/libGL.so.1 libGL.so.1

(so basically: ln -sf /usr/lib/nvidia-[VERSIONHERE]/libGL.so.1 ~/.dropbox-dist/[VERSIONHERE]/libGL.so.1

6) start up dropbox

$ dropbox start

Hopefully this helps, this worked for me. What it does is force dropbox to use the libGL installed on your system after nvidia overwrites it, by placing a symbolic link to the nvidia libGL in place of the one dropbox was installed with. After backing up the old dropbox libGL, of course.