[AYBABTME]

inotify has a limit on how many watches can be held. I don't think that 300k limit is particular to Dropbox, any tool working on the same principle will hit that limit.

[ars]

They should watch the directory, not the file.

The limit is found here: /proc/sys/fs/inotify/max_user_watches and defaults to 8K, not 300K, so I don't think it's the cause of this problem.

[AYBABTME]

You're right, I was mistaken. The limit is a user limit.