In this article we will look how to temper appetite for your RAM and CPU resources by following processes called mdworker and mds, that can cause unpleasant troubles for your Mac.

In the “Activity Monitor” you may notice several processes called mds and mdworker on Mac. They have no icon, and they are constantly running. Do not worry, they are harmless. But the following processes that can cause unpleasant troubles.

In fact, these are very noble processes that are responsible for indexing data on a Mac, that is, as many have already guessed, they are working directly with Spotlight. But sometimes this duet may unjustifiably burden the computer, leaving miserable bits of free RAM and CPU.

What is mds Process?

The mds process is a metadata server. The mds process controls the index used to quickly find results.

What is mdworker Process?

The mdworker process, is the “worker” of the metadata server, but does all the work of actually indexing all files of operating system to make a quick search possible.

What are mds and mdworker Processes on macOS Activity Monitor?

Why are mds and mdworker processes use a lot of RAM and load the CPU? If you recently transferred your files and applications from one Mac to another or downloaded many new files, it is quite normal that mds and mdworker run at full capacity, thereby using a lot of memory and processor. These processes are working to create an index all of them, which will then provide a quick search.

Read more: How to View Running Processes in macOS?

Indexing usually takes completely an hour, although it may depend on your hardware speed (CPU/HDD/SDD). By default, Spotlight is configured to use a little part of your OS potential. But it could, will be very voracious, if you bring a massive of data to your system. If you use a computer for other operations that require a lot of resources, the indexing process should stop temporarily. But if your Mac remains inactive and you are connected to a power network, Spotlight will use all the available resources needed to create the database.

Recreating the Spotlight Index

If these processes never finish work and constantly use your processor and memory several days after the start of indexing, there is a chance that your index is damaged. Fortunately, you can fix this by restoring the Spotlight index.

Solve the Problem

First Way

Since these processes are caused by Spotlight, you need to pacify them (do not be afraid, this is not for too long time. I understand perfectly well, how great it makes life easier for many “apple users”).

  • To do this, go to the terminal and enter this command:
sudo mdutil -a -i off
  • Spotlight is now completely disabled, we go into monitoring and rejoice;
  • Now turn on the search for everything back:
sudo mdutil -a -i on

Second Way

You can run the following command in the terminal:

    sudo mdutil -E /

Your entire Spotlight index will be erase and rebuild. Once this process is complete, mds and mdworker should stop using your resources.

It’s the best time to ask questions and give us your feedback in comments.


Hi there! My Name is Vincent Lago! My goal is to share insightful reviews, guides, and manuals for people looking to know more about current solutions for Apple hardware and OS. I have years of technological background knowledge including owning a custom iMacs & PCs which was using for different types of business. And now, I want to share my experience with you.


  1. Vincent, I did your sudo thing to get rid of mdworker but now it asked for password and showed a key, now what do I do? Thanks

    • Vincent Reply

      Hi, Kelly! Just continue to work on your Mac, if you did everything correctly then the process will not run in the future.

    • Hey Kelly, did you enter your password? ‘Sudo’ terminal operations require an admin password to be successfully ran.

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