How to Customize the Mac Mail Sidebar and Favorites in 2026

To customize the sidebar in Mac Mail, drag any mailbox into the Favorites section at the top (or click the Add Mailbox button beside Favorites), drag mailboxes up or down to reorder them within an account, and collapse sections you don't use with their disclosure arrows. Press Control-Command-S to show or hide the sidebar, and Option-Shift-Command-H for the Favorites bar.

The Mail sidebar starts tidy and then grows a mailbox for every project, client and newsletter you ever filed. Add a second account and the list doubles. This guide covers each part of the sidebar on macOS 27: what the sections are, how Favorites and the Favorites bar work, how to add, move and rename mailboxes, how to make the sidebar easier to read, and the usual reasons a mailbox or the whole sidebar goes missing. Steps follow Apple's current Mail User Guide; on older macOS versions the Mail menu says Preferences where these steps say Settings.

What's in the Mac Mail sidebar

The Mac Mail sidebar is the column on the left of the Mail window that lists your mailboxes, grouped into sections. Apple's sidebar guide says it holds mailboxes, folders and flagged items for your accounts, with sections such as Favorites and Smart Mailboxes. From top to bottom you'll usually see these:

Every section can be folded away. Move the pointer over a section's name and a disclosure arrow appears beside it; click the arrow to hide or show what's inside, as Apple's missing-messages article describes. Folding a section hides nothing for good: the mailboxes and messages are all still there, one click away.

How to show, hide or resize the sidebar

Show or hide the Mail sidebar with View > Show Sidebar or View > Hide Sidebar, or press Control-Command-S. Apple lists the same shortcut on its Mail keyboard shortcuts page.

To change its width, drag the separator bar between the sidebar and the message list to the left or right. Apple's sidebar guide adds a detail that catches people out: drag that bar all the way to the left and the sidebar is hidden rather than just narrow.

That's exactly how I lost mine the first time. I was widening the message list on a laptop, pulled the divider a little too far, and the mailboxes were gone. Control-Command-S brought them straight back, and now I hide the sidebar on purpose when I'm working through an inbox on a small screen.

How to add a mailbox to Favorites in Mac Mail

Favorites in Mac Mail is the first section of the sidebar, kept for the mailboxes you open most. Apple's favorite mailboxes guide gives two ways to add one:

1. Open Mail and find the mailbox you want in the sidebar.
2. Drag it from its account section up into Favorites.
3. Or click the Add Mailbox button at the top of Favorites, pick the mailbox from the pop-up menu, then click OK. Mailboxes that are dimmed in that menu are already favorites.

The pop-up menu is also where you'll find All Inboxes, the combined inbox for every account. Apple's guide for people switching to Mail gives this as the way to see all your inboxes in one place. Once it's there, click the arrow beside All Inboxes to see each account's inbox listed under it, per Apple's sidebar guide.

I keep Favorites short on purpose: the mailboxes I open every day, and nothing I check once a week. Five or six entries can be read at a glance; twelve can't, and then Favorites is just a second copy of the account list.

How to remove a mailbox from Favorites

In the sidebar, Control-click the mailbox in Favorites and choose Remove from Favorites. On the Favorites bar, drag the mailbox off the bar. Both steps come from Apple's favorite mailboxes guide.

Removing a favorite only takes away the shortcut. The mailbox itself, and every message in it, stays in its account section where it always was. That's different from Mailbox > Delete Mailbox, which is covered further down and can't be undone.

How to use the Favorites bar

The Favorites bar is a row of mailbox buttons across the Mail window, and it shows the same favorite mailboxes as the Favorites section of the sidebar. Turn it on with View > Show Favorites Bar, or press Option-Shift-Command-H; the same command hides it again, per Apple's favorite mailboxes guide.

• Add a mailbox: drag it from the sidebar onto the bar.
• Open a mailbox: click its button on the bar, or choose Mailbox > Go to Favorite Mailbox and pick one from the list.
• File messages: select them and drag them onto a button on the bar.
• Remove a mailbox: drag it off the bar.

The bar earns its space when you keep the sidebar hidden. On a 13-inch screen I'd rather give the message list the room and reach my mailboxes from a single row at the top. On a big external display, the sidebar has room to spare and the bar is just a second copy of the same list, so I leave it off there.

How to reorder, add and rename mailboxes

Mailboxes inside an account section can be moved, created and renamed straight from the sidebar. Reordering works within one account: Apple's mailboxes guide describes dragging a mailbox to a new position inside its own account, not across accounts.

Reorder mailboxes

Drag a mailbox to a new spot within its account in the sidebar. Standard mailboxes such as Inbox and Drafts are listed first, per Apple's mailboxes guide, and the mailboxes you create are listed along with them.

Create a new mailbox or subfolder

1. Choose Mailbox > New Mailbox.
2. Click the Location pop-up menu, then pick where it goes: an account, On My Mac, or an existing mailbox.
3. Type a name and click OK.

Picking an existing mailbox as the location creates the new one inside it, like a subfolder, per Apple's mailboxes guide. Some work email systems include public read-only mailboxes, and Apple notes you can't create mailboxes inside those.

For anything I might need on my phone, I create the mailbox under the account. On My Mac is where I park old project mail I'm keeping for reference and never need away from my desk.

Rename a mailbox

Click a mailbox once to select it, then click its name again (or force click it) and type the new one, as Apple's rename guide explains. A few limits apply:

• For an IMAP account, make sure the account is online before you rename.
• The new name can't already belong to another mailbox.
• Some mail servers reject certain characters, such as a forward slash (/).
• Renaming a mailbox's folder in the Finder may not show up in Mail, so always rename inside Mail.

How to add Smart Mailboxes to the sidebar

A Smart Mailbox is a saved search that sits in the sidebar and fills itself with matching messages, wherever they're filed. Create one with Mailbox > New Smart Mailbox, give it a name, set conditions such as From or Subject, choose whether messages must match any or all of them, and click OK, per Apple's Smart Mailboxes guide.

Smart Mailboxes pair well with Favorites. A mailbox for unread mail from your manager, or for anything flagged this week, can be dragged into Favorites like any other. If the built-in Today Smart Mailbox seems to be missing, Apple says to hover over the Smart Mailboxes section and click its disclosure arrow. For the search conditions worth saving, see our Apple Mail advanced search guide.

How to make the Mail sidebar bigger or smaller

Mail has no sidebar text setting of its own. The size comes from a Mac-wide setting: open System Settings, click Appearance, and pick small, medium or large from Sidebar icon size. Apple's Appearance settings page says it covers the Finder sidebar and the sidebar in apps such as Mail, News and Photos, and that the sidebar text changes size along with the icons.

I went to Large after a long day of reading mailbox names at Small, and the Finder came along for the ride, which I didn't mind. If you only want the inbox and the emails themselves to be bigger, the Mail settings for that are in our guide to fonts and text size in Mac Mail.

Flags in the sidebar

Flagged messages collect in a Flagged mailbox, which Apple's flag guide says shows up in the sidebar once you're using more than one flag. Click its disclosure arrow, then click a flag's name, click again and type a new label to rename it, for example Red to Urgent.

Renamed flags turn that corner of the sidebar into a small to-do system. Mine read Reply, Chase and Read later, which tells me more at a glance than a row of colors ever did. Our guide to color coding in Mac Mail goes further with flags and colors.

Why a mailbox is missing from the Mail sidebar

A mailbox that has vanished from the Mac Mail sidebar is almost always hidden, not deleted. Work through these checks from Apple's missing-messages article in order:

1. The sidebar itself is hidden. Press Control-Command-S or choose View > Show Sidebar.
2. A section is collapsed. Hover over each section name and click the disclosure arrow to expand it.
3. The account is turned off. Open Mail > Settings > Accounts, click the missing account in the list, and tick Enable this account if it's unticked.
4. It was renamed in the Finder. Apple's rename guide warns that Finder changes may not show up in Mail. Rename it back, or rename it inside Mail.

If the mailbox is there but looks empty, the sidebar isn't the problem. Mail's message filter can hide read messages (toggle it with Command-L), and on macOS Sequoia 15.4 or later the category buttons above the list can show only one category, per the same Apple article. Click the selected category again to see everything, or turn categories off with Show Mail Categories in the View Options menu.

One more oddity: Sent, Drafts, Junk or Trash messages landing in an unexpected mailbox. For IMAP accounts, Mail > Settings > Accounts > Mailbox Behaviors decides which mailbox stores each kind, and Apple's Mailbox Behaviors page suggests leaving Mail's choice unless your email provider tells you otherwise.

A sidebar setup that stays short

When I added a second work account, the sidebar went from comfortable to a scroll. What fixed it was treating Favorites as the place I work and the account sections as storage I rarely open. This is the setup I've kept since, offered as a starting point rather than Apple's advice:

• Favorites: All Inboxes at the top, then a Waiting mailbox for things I've chased, then the one or two project mailboxes active this month.
• Smart Mailboxes: one for flagged mail, dragged into Favorites, and the built-in Today left as it is.
• Account sections: collapsed, opened only to file or find something old.
• On My Mac: a single archive mailbox for finished projects.
• Sidebar icon size: Large on the laptop.

The Waiting mailbox does more work than its size suggests. When I send something that needs an answer, I drag my copy from Sent into it, and once a week I scan that one mailbox instead of searching Sent for loose ends. Projects move out of Favorites when they end, so the list never creeps back to where it started. For filing finished mail out of the inbox, our guide to archiving emails in Mac Mail covers the Archive mailbox and its shortcut.