Nautilus-dropbox suddenly stuck ("Starting...") after reboot on four different machines

[dushoff]

I have four different Ubuntu 24.04 machines that have all been running nautilus-dropbox successfully for months to years, some since Ubuntu 20.04. Starting some time last week, they all successively stopped syncing after reboot. I am not aware of anything that I changed (and it doesn't seem likely that I changed anything on all four machines).

My dropbox status, even after hours, now always says:

🌑 dushoff@siX:~/screens$ dropbox status
/usr/bin/dropbox:613: DeprecationWarning: isSet() is deprecated, use is_set() instead
  if self.stop_event.isSet(): break
Starting...
🌑

dropbox update succeeds but does not change the situation.

I get occasionaly warnings about fs.inotify.max_user_watches, but this seems to be a red herring. Warnings don't always stop even when I increase this value well beyond my folder number, and behaviour doesn't change even when the warnings stop.

Here is some more information:

🌑 $  lsb_release -a
Distributor ID: Ubuntu
Description:    Ubuntu 24.04.1 LTS
Release:        24.04
Codename:       noble

🌑 $ dpkg -l nautilus-dropbox
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name             Version              Architecture Description
+++-================-====================-============-========================>
ii  nautilus-dropbox 2019.02.14-1.2build2 amd64        Dropbox integration for >

I'm not using firewalls or vpn. The machines are in two different physical locations (two at home and two at work).

I tried the dropbox "headless" approach on one machine. This installs but produces the same forever "Starting..." behaviour. I tried other things, but this one seems potentially relevant to the nautilus-dropbox problem.