Dropbox gives me pop-up errors about not being able to monitor the file system (that quickly disappear) when it starts up but it still seems to work ok, why is that?

  • On what operating system are you running the Dropbox client? Are you able to obtain the full text of the error message?
    – jeff
    Commented May 8, 2012 at 1:13

2 Answers 2


On Linux, the Dropbox client is subject to a default system limit on the number of directories it can monitor for changes. There is a warning regarding this, along the lines of:

Unable to monitor filesystem

Please run: echo 100000 | sudo tee /proc/sys/fs/inotify/max_user_watches and restart Dropbox to correct the problem.

This comes up often in the Dropbox Forums, and they have a mention of it in their "Why aren't certain files on one computer syncing to another?" document:

Monitoring more than 10000 folders

The Linux version of the Dropbox desktop application is limited from monitoring more than 10000 folders by default. Anything over that is not watched and, therefore, ignored when syncing. There's an easy fix for this. Open a terminal and enter the following:

> echo fs.inotify.max_user_watches=100000 | sudo tee -a /etc/sysctl.conf; sudo sysctl -p

This command will tell your system to watch up to 100000 folders. Once the command is entered and you enter your password, Dropbox will immediately resume syncing.

  • This does not explain the message suddenly appearing, when not changing the number of folders or files it needs to monitor. I changed files but not the number of files or directories. Next day I see that message. Any explanation for that? Commented Jul 19, 2016 at 12:35

After multiple tries I was still getting the "unable to monitor filesystem" error. I finally figured out why:

100,857 Files, 15,009 Folders

I had to bump my max_user_watches to a higher number.

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