How to flag an email in Apple Mail on Mac: steps, Flagged mailbox, unflagging

A flag is a colored marker you put on an email. It tells you the message needs attention later. Flagging does not move the message. It stays in its mailbox, so your Inbox, a folder, or Sent still shows it. A flag only helps if you come back to it. So this page gives you the steps first, then where flags show up, how to clear them, and what to do when something looks wrong.

Flag one message or several at once

Click a message in the list to select it. To flag several messages, hold ⌘ and click each one. To select a run of messages in a row, click the first one, then hold ⇧ and click the last one. Then click the Flag button in the Mail toolbar and choose a flag. Mail applies the flag to every selected message in one action.

Check the result before you move on. Open the message and look at its header, where the flag shows. If nothing changed, the message was probably not selected. Click it once so the highlight shows, then repeat the Flag step. That fixes most cases where a flag seems to fail.

Selection matters more than most people expect. Flag acts on whatever is highlighted, not on whatever your cursor touched last. If three messages are highlighted and you click Flag, all three get the flag. A common mistake is to click one message, scroll, and then flag a different group that is still selected. Look at the highlight first.

Choose a flag and understand the Flagged mailbox

When you click Flag, the menu lists flag colors. Apple's guide uses Red as its example, so look for that color first. A third-party vendor, Canary Mail, says Mail on Mac has seven fixed colors: red, orange, yellow, green, blue, purple, and gray. Apple's guide does not confirm that count. Open the menu on your own Mac and count them.

The Flagged mailbox does not always appear. Mail shows it in the sidebar only when more than one flag is in use. Flag one message in red, and you will see no Flagged mailbox. Flag a second message in another color, and the mailbox shows up. This catches people out, and it is the first thing to check when Flagged seems to be missing.

Here is a worked example. On Monday you flag a contract in red. The sidebar shows no Flagged item, which looks like a failure but is not. On Tuesday you flag a vendor invoice in a second color. Flagged now appears, with both messages inside it. Click Flagged to see them together, then clear each flag as you finish the task.

• A flag shows in the message header.
• The message stays in its original mailbox.
• Flagged appears in the sidebar only when more than one flag is in use.
• Clear Flag removes the flag. It does not delete the message.

Clear a flag when the task is done

Select the flagged message, click the Flag button, and choose Clear Flag. The flag comes off, and the message leaves the Flagged list. Clear flags as each task ends. A list of flags that never clear turns into a second inbox, and that defeats the point.

Clearing works on several messages at once. Select them all, click Flag, and choose Clear Flag. Mail applies the change to every selected message. Then check the Flagged mailbox, which should now show fewer messages. If one stays, click it once and repeat the step.

Be careful with the selection when you clear. Clear Flag acts on whatever is highlighted, the same as Flag does. Check the highlight first. Clearing a flag on the wrong message is easy to miss. If a flag seems to have vanished, look in the mailbox where the message lives, then check whether Clear Flag was chosen by mistake.

Rename a flag so it says what you mean

Renaming changes the label, not the color. Apple's example renames Red to Urgent, which is a good model for your own set. Expand Flagged in the sidebar with its disclosure triangle. Click the flag name, click it again, and type the new name. Then press Return to save it.

Good names say what the flag means to you. Waiting on reply, Pay this week, and Read tonight all work. Keep the set short. Three names you use every day beat ten you never check.

Names also help when someone else uses your Mac. A label like Urgent tells them more than a color alone. Pick names that you would understand a week from now, without the message in front of you.

Find every flagged email in one place

Click Flagged in the sidebar to see every flagged message in one list. The messages stay in their own mailboxes. Flagged is a view, not a folder you move mail into. Clear flags from inside Flagged the same way you do anywhere else, with Flag and Clear Flag.

If Flagged is missing, you are using only one flag. Flag a message in a second color, and the mailbox comes back. Keep this in mind when you show a colleague how flags work. They may look for a mailbox that does not appear yet.

Use Flagged as a to-do list for mail. Work from the top, open each message, reply or file it, then clear its flag. The list gets shorter as you go. If it keeps growing, flag fewer messages each morning and be stricter about what counts.

A week of flags, worked through

Monday starts with a full Inbox. You flag three messages in red: a quote that needs a reply, a form to sign, and a question from your manager. The sidebar shows no Flagged item, because only one flag is in use. That is expected.

Tuesday you flag an invoice in a second color. Flagged appears in the sidebar. You open it and see four messages in one list. You reply to two, file one, and clear the flag on each as you finish. Flagged now holds two messages.

Wednesday you rename the red flag to Waiting on reply. The label is clearer than the color alone. Your list reads the same way, but you can scan it faster. You clear the signed form and the reply you sent, and select both before you click Flag so the change applies to both.

Thursday you notice a flag is missing from a message you wanted to keep track of. You look in its mailbox, find the message, and see that Clear Flag was chosen on a selection that included it. You flag it again and move on.

Friday you clear everything left in Flagged. The sidebar item may disappear again, because only one flag remains in use, or the list may be empty. Either result is fine. The week's flags did their job.

Flag from iCloud.com and check the shortcut

On iCloud.com, you flag from the web app, not from the Mac app. Select a message, or hold Command and click several. Then click Mark, or the More button, and choose Flag. Flagged messages show a flag icon in the list. For one message in an open conversation, use the More button in the bottom-right corner, then Flag.

Apple's page does not explain how to clear a flag on iCloud.com. If you cannot find a clear action there, use the Mac app, where Apple's steps are documented. Flags you set in one app should still appear when you check the same account elsewhere, though sync can lag.

Apple's iCloud.com shortcut table lists Shift-Command-L for flagging. That table covers the web app. Apple's Mac Mail shortcut table has no flag entry, and the only related entry is Shift-Command-U, which marks a message read or unread. Some third-party guides say Shift-Command-L also works in Mac Mail. Apple does not confirm that. Test it on a selected message. If nothing happens, use the toolbar.

Common mistakes that make flags look broken

• Flagging with nothing selected. Click the message so it highlights, then click Flag.
• Expecting the Flagged mailbox after one flag. Mail shows it only when more than one flag is in use.
• Mixing up flags with read status. Mark as read or unread uses Shift-Command-U, a separate action.
• Thinking a flag moves the message. It stays in its mailbox and also appears in Flagged.
• Expecting every device to match. Community reports describe Gmail flags not syncing across devices. Apple does not document this.

If flags do not sync, check the account first. Community suggestions include rebuilding the mailbox or re-adding the account. Apple's flag guide does not cover either fix, so read Apple's Mail account steps before you change anything. Re-adding an account changes its settings, so note your account details first.

Build a daily flagging routine

Flags work best inside a routine. Each morning, scan the Inbox and flag mail that needs a reply that day. Around midday, open Flagged and work through it. Before you log off, clear the flags on anything you finished. The flags left over tell you what carries into tomorrow.

Email takes a large share of the workday. McKinsey research from 2012 put email at 28% of the workweek, about 11.2 hours, for the average knowledge worker. That figure reaches this page through Clean Email, not McKinsey's own report, so treat it as a rough guide.

Apple Mail accounts for a large share of email opens. Litmus counts it at 76.56% in its September 2026 report. That count includes Mail Privacy Protection opens, which do not reliably show the app or platform, so read it as a rough share.

A Microsoft study from April 2025 found workers spent over 11 hours a week on email before Copilot. Copilot users saved nearly 3 hours a week, about 25%. These numbers measure email time in general. No source I checked measures how people use flags.

Lazur helps when you cannot find a control. Hold ⌥ ⌘, then ask where the Flag button is. Lazur draws a circle and a label around it on your screen and answers out loud. Ask how to rename a flag, and Lazur guides you one click at a time, waiting for each click before it moves on. You do the clicking.

Lazur listens and looks at your screen only while you hold the shortcut. Audio and the screenshot go to AI providers to produce an answer, and they are not stored. Content is never used to train AI models. Lazur has a 3-day Pro trial with no credit card, and it starts when you first open the app. Plans and AI action limits are on the pricing page.

Related Mail tasks to set up next

Once flags make sense, sorting comes next. Create a rule to sort incoming mail in Apple Mail on Mac can sort mail as it arrives. If a few senders matter most, use the VIP mailbox in Apple Mail on Mac keeps them in one place. To find everything from one person, search emails by sender in Apple Mail on Mac. For the app itself, see AI assistant for Apple Mail.

Check your Mail version before you follow the menu

Apple's flag guide does not name the macOS or Mail version it covers, and this page does not either. The steps follow that guide and the Flag button in the toolbar. If your toolbar looks different, look for a flag control in the toolbar and in the Message menu. Some guides list Message > Flag > Toggle Flag. Apple does not confirm that path, so check your own Message menu before you rely on it.