What is suggestd on a Mac?

suggestd is a macOS background process that finds suggestions in your mail and messages, the ones Siri Suggestions offers in places like Spotlight and Mail. It is part of macOS, it is safe, and it usually sits idle. It gets busy for a while after a lot of new mail or messages arrive, for example after you add a mail account or a big sync finishes, and then it settles down by itself.

If you found it near the top of a list because your Mac is warm or the fans are running, the short version is this: wait, and check again in an hour. Most of the time that is the whole fix.

What suggestd does

The name is short for “suggestions daemon”. A daemon is a program that runs in the background without a window. This one reads the content that apps like Mail and Messages hold and works out what might be worth suggesting back to you, such as contact details or an event mentioned in an email. To do that it has to look at new items as they come in, so its work follows your inbox.

It belongs to a small family of macOS processes that work on suggestions. Two of its neighbours are knowledge-agent, which learns usage patterns for Siri and suggestions, and corespotlightd, which indexes content from apps for Spotlight. You will often see them busy at the same moment, because new mail gives all three something to do. What is corespotlightd on a Mac? covers the Spotlight side.

None of this is a sign of a problem. A Mac that has just downloaded two years of mail is supposed to be busy.

Why suggestd is busy

Think about what changed shortly before you noticed it.

• A big mail sync. You added a Mail account, or turned Mail back on after a long break, and thousands of messages arrived at once. suggestd goes through them.
• A macOS update. After an update, macOS often rebuilds its indexes and suggestion data. Why is my Mac slow after a macOS update? explains the wider pattern.
• A fresh setup or restore. A new Mac, or one restored from a backup, has a lot of existing content to look through for the first time.
• A lot of messages in a short time. A busy group chat or a large import into Messages can do the same on a smaller scale.

In all of these cases the work is finite. When suggestd has read what is new, its CPU use falls back to nearly nothing. If it stays busy for days with no new mail arriving, that is worth a second look, and the steps below help.

How to see whether suggestd is the problem

You do not need to guess. Check three things.

1. Is it actually high, and for how long? A burst of CPU use for ten or twenty minutes after a mail sync is normal. Hours of it with a quiet inbox is not.

2. Is it the only busy process? Often suggestd is one of several, along with Spotlight indexing and the other helpers named above. If they are all busy together, the Mac is catching up on new content, and the cause is the event, not suggestd.

3. What is the number? In Terminal, this prints its current CPU use and memory, read-only:

ps -o pid,%cpu,rss,comm -p $(pgrep -x suggestd)

Run it a few times a minute apart. ps counts each processor core as 100%, so on a Mac with several cores a busy process can read above 100. If %cpu keeps dropping, it is finishing. If it stays high, note the time and see whether it lines up with Mail or Messages doing something.

Foreman shows the same thing without Terminal. On its Processes page suggestd appears as “Siri Suggestions”, with the real name beside it in grey and the CPU, memory, disk and network columns next to it. Its CPU figure is a share of the whole Mac, with the Mac’s total above the column, so it reads lower than the ps number. Click the CPU column to sort and you can see at a glance whether it is at the top or just one of many. Foreman is a $12 Task Manager for macOS, free for 24 hours.

What you can safely do

Wait. For a sync or an update, this is the right answer. Leave the Mac plugged in and awake for a while so it can finish.

Do not end it. You can end it, but macOS starts it again the next time it needs it, and the work resumes. Ending it gains you very little and loses the progress it had made.

Slow it down instead, if it gets in the way. suggestd runs under your own account (the User column shows your name), so Foreman can put it in Efficiency Mode. While it is in the background it then runs at background priority and is held to about a quarter of the processor time it would take, so the catch-up takes longer and leaves more room for your apps. How much that helps depends on how busy the Mac is. Turn it off again from the same menu and it runs at full speed at once.

Restart the Mac if it has been stuck for days. A restart gives every suggestion process a clean start. It is the gentlest fix for a process that seems to be going in circles.

Check Mail for a problem account. If suggestd is busy right after you opened Mail, and Mail itself is slow, one account may be re-downloading its messages. Waiting for Mail to finish is the cure. How to find the app to blame when your Mac is slow has the general method.

Can you turn Siri Suggestions off?

Yes, at least in part. On macOS 14 Sonoma the switches are in System Settings > Siri & Spotlight. Later versions split them between the Siri settings (called Apple Intelligence & Siri on Macs that have it) and a separate Spotlight section. In the Siri settings you can choose, app by app, whether Siri shows suggestions in that app and learns from it, and in the Spotlight settings you choose which kinds of results appear. Turning them off may give macOS less to do with your mail and messages, and it means fewer things suggested to you in Mail and Spotlight.

Be honest with yourself about the trade. Suggestions are a convenience, not a necessity, so if you never use them there is little to lose. If you do use them, a few busy minutes after a sync is a fair price. Either way, do not go looking for ways to delete suggestd itself from the system. It is part of macOS, and macOS expects it to be there.

When it is worth worrying

Almost never, but these are the cases that deserve attention:

• It has been using a lot of processor time for several days, with no mail or message activity to explain it.
• The Mac is hot or the battery drains fast, and suggestd is at the top every time you look.
• Mail or Messages is also slow or stuck.

In those cases restart first. If it comes back and keeps going, check that macOS is up to date in System Settings, General, Software Update, since fixes for background processes arrive through updates.

The short version

suggestd looks for suggestions in your mail and messages. It is busy when a lot of new content has arrived, and quiet the rest of the time. Wait it out after a big sync, restart if it never settles, and leave the process itself alone. If you want to watch it settle, Foreman shows it by its plain name, sorted by CPU, next to whichever of its neighbours are busy at the same time.