If the file system watcher (used to calculate the current workspace changes) fails because it overran the maximum number of watches, the Pending Changes view will display a warning message informing the user to increase this limit.
To increase this parameter, run the command below in your Linux/mac machine. This way, Plastic can use the system watcher to calculate the pending changes faster.
You can increase its value by executing:
sudo sysctl fs.inotify.max_user_watches=524288