baloo_file error: KDE Baloo File Indexer has reached the inotify folder watch limit. File changes will be ignored.

Case: Ubuntu 18.04 (KDE), Baloo search index reached max inotify watchers: search in Dolphin (Ctrl+F) doesn’t return search results for new files and so does KRunner (Alt+F2).

Solution

Checking the current number of inotify watchers:

cat /proc/sys/fs/inotify/max_user_watches

To check Baloo service status:

balooctl status

Persistently set inotify watchers to a big number:

sudo su
echo "fs.inotify.max_user_watches = 500000" >> /etc/sysctl.conf
exit
balooctl reload
balooctl status

Upon entering that last command, the index size should’ve increased.

Complementary Notes:

Mounted drives (secondary HDD, for example) are excluded from the index by default. Can be managed form File Search – System Settings Module.

Indexing can be disabled from File Search – System Settings Module.