Everything you need to know about HIUTIL

There are numerous macOS users have asked this question online : What is hiutil and why it is taking up the majority of my computer processing power?

This article will try to shed some light on what the hiutil process really is, as well as show you a few ways that you can stop or disable hiutil in case it hogs up system resources.

What is hiutil?

hiutil, stands for “help index utility”, is a system program in MacOS which was designed to create and examine .helpindex files. Helpindex files are generated to enable quicker Help menu searches and Spotlight searches. You can use sudo find / -name "*.helpindex" to display all of them

According to xcode manpages, hiutil is used to create .helpindex files in the Latent Symantic Mapping (LSM) help format and .cshelpindex files in the Spotlight help format. It is also capable of examining Spotlight help indices.

hiutil high CPU usage – what to do?

Whenever you see hiutil takes up a large chunk of system resources, usually CPU usage, the program is indexing your hard drive in order to make sure the next time you use Spotlight or do any Help search, the experience will be as fast as it can be.

The program may fork itself into several other child process, all named hiutil. Sometimes, you may see another process named mdutil, which reads all metadata and index them.

Most of the time, hiutil running is normal behaviour and you should leave the process alone. However, in case it interrupts you in the middle of an important working session, you can force kill it using Activity Monitor.

If you want to make sure the process never automatically run again, you can also remove the executable at /usr/bin/hiutil or rename it. But this action is not recommended, since it can cause system instability or even malfunction.

When this process is running, you might – depending on your OS – see an index progression bar in your spotlight window if you start to enter text (or enter “indexing”).

View indexing status

If hiutil is running in conjunction with mdutil , you can see the status of the volume being scanned by running mdutil -s <volumename>.

You can go to System Preferences > Spotlight and fine-tune each options in Search Results and Privacy panes to alter the scanning behaviour. As changes are made to actively scanned directories, the indexer is invoked immediately.

Stop hiutil

If your computer keeps indexing and you can’t seem to make it stop, you might want to consider adding your internal drive to the “Private” list using the Disk Utility app on your Mac. This could help the indexing process finish faster, if not right away.

In case hiutil process is working in conjunction with mdutil, you have another option. Just run sudo mdutil -E / . to force Spotlight to create a new index file and the indexing process should be stopped and scheduled to run at a later moment.

Leave a Comment