I've been running Dropbox on my Ubuntu 18.04 desktop just fine for months. Today, I noticed the application had stopped, so I tried to start it again and it said "Authentication is needed to run '/bin/sh' as the super user." Whether or not I authenticate, it then goes into "Starting..." status forever.
I've tried removing the current installation and reinstalling, but that doesn't make a difference.
Here's the terminal output:
dropbox: locating interpreter
dropbox: logging to /tmp/dropbox-antifreeze-PZrvIR
dropbox: initializing
dropbox: initializing python 3.5.4
dropbox: setting program path '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/dropbox'
dropbox: setting home path '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94'
dropbox: setting python path '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94:/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/python-packages-35.zip'
dropbox: python initialized
dropbox: running dropbox
dropbox: setting args
dropbox: applying overrides
dropbox: running main script
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/cryptography.hazmat.bindings._constant_time.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/cryptography.hazmat.bindings._openssl.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/cryptography.hazmat.bindings._padding.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/psutil._psutil_linux.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/psutil._psutil_posix.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/linuxffi.pthread._linuxffi_pthread.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/linuxffi.fcntl._linuxffi_fcntl.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/linuxffi.sys.compiled._linuxffi_sys.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/cpuid.compiled._cpuid.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/linuxffi.resolv.compiled._linuxffi_resolv.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/tornado.speedups.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/linuxffi.gnu.compiled._linuxffi_gnu.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/posixffi.libc._posixffi_libc.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/librsyncffi.compiled._librsyncffi.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/PyQt5.QtWebKit.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/PyQt5.QtCore.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/PyQt5.QtNetwork.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/PyQt5.QtGui.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/PyQt5.QtWebKitWidgets.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/PyQt5.QtWidgets.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/PyQt5.QtPrintSupport.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/home/eater/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/PyQt5.QtDBus.cpython-35m-x86_64-linux-gnu.so'