How to Search Across All Mailboxes and Accounts in Outlook

To search all mailboxes in Outlook at once, click into the search box above your message list, open the Scope menu on the contextual Search ribbon tab, and choose All Mailboxes. Outlook reruns your query against every mail data file that's open in your current profile - your inbox, its subfolders, any archive file, and every other account you've added - and returns one merged results list instead of one per account.

That single click solves the most common version of the problem: a search that only checked your current folder. It does not solve all of them. All Mailboxes only reaches accounts inside your active Outlook profile, and by design it skips a shared or delegated mailbox that's open through Open these additional mailboxes, even though that mailbox sits right there in your folder pane. If one specific account keeps not showing up, that's almost always why - not a broken search index.

This is also the scope to use when you want your archive and your inbox searched together rather than as two separate hunts. If your archive is an Outlook Data File you opened yourself, or an online archive Microsoft manages for a Microsoft 365 mailbox, All Mailboxes includes it automatically as long as it's currently open in the profile - no extra step beyond the one you're about to take.

Before you start#

The All Mailboxes scope works from inside Outlook itself, so there's nothing to install or turn on ahead of time. A few things do affect whether it actually reaches everything you expect, and checking them first saves you from troubleshooting a scope setting when the real problem is somewhere else.

• Every account you want included is added under File, then Add Account, in the same Outlook profile you're searching from.
• You know which Outlook you're running - classic desktop Outlook, the new Outlook for Windows, Outlook for Mac, or Outlook on the web - because the scope options differ by platform.
• Cached Exchange Mode is turned on for any Microsoft 365 or Exchange account whose full history you want searchable without a live connection.
• Any account you added recently, or any large PST you just opened, has had time to finish its first local sync - a brand-new mailbox has nothing indexed yet.
• You're not actually trying to reach a shared or delegated mailbox. That needs a different approach, covered later in this article, not All Mailboxes.

Search every mailbox and account at once#

This is the sequence for classic desktop Outlook, the version most people mean when they ask how do I search every account at once in Outlook. It takes about ten seconds the first time and none of it needs to be repeated once you set a default in the last step.

1. 1

   Click into the search box

   Press Ctrl+E, or click directly in the search field above your message list. Outlook switches the ribbon to a contextual Search tab.

2. 2

   Open the Scope menu

   In the Search tab's Scope group, you'll see five options: Current Folder, Subfolders, Current Mailbox, All Mailboxes, and All Outlook Items.

3. 3

   Choose All Mailboxes

   This searches every mail data file currently open in your profile - each added account plus any archive or PST file you've opened - rather than just the folder or account you're standing in.

4. 4

   Type your query and press Enter

   Outlook runs the same search across every included mailbox and merges the hits into one list, so you don't have to repeat the search per account.

5. 5

   Check which account each result belongs to

   If the account isn't shown, right-click a column header in the results list and add Account, or use the arrangement menu to sort by folder, so you can tell where each match lives.

6. 6

   Narrow the merged list with search operators

   from:, subject:, and hasattachment: still work across the wider scope - they filter the combined results rather than replacing All Mailboxes with something narrower.

7. 7

   Optional: make All Mailboxes your default

   Go to File, then Options, then Search, and change the results setting to search all open data files by default, so you don't have to reselect the scope on every search.

Platform differences: where All Mailboxes reaches, and where it doesn't#

The steps above describe classic desktop Outlook for Windows, which has used this scope model for years. The other places you might be searching from behave differently enough that following the same steps won't work.

If you regularly work across more than one of these - a company laptop running new Outlook, a personal Mac, a phone browser - the honest takeaway is that search multiple accounts Outlook desktop and search multiple accounts Outlook web are two different problems with two different answers, and treating them as the same one is where most of the frustration comes from. Confirm the scope on whichever surface you're on before deciding a message doesn't exist.

Why All Mailboxes search still misses one account#

Most All Mailboxes failures trace back to one of a handful of causes, and each has its own fix rather than a general one. The table below covers the ones that come up most.

A faster way to search everything you've connected#

Outlook's All Mailboxes scope gets you most of the way, but it only reaches what's already indexed locally, in the active profile, at the moment you search. If you're hitting one of the gaps above often enough that it's slowing you down, a client built to search across accounts by default handles it differently.

AI Emaily connects Gmail, Outlook, and IMAP accounts - shared or personal - into one continuously indexed inbox, so there's no profile to switch and no shared mailbox to search separately. Its search also understands a plain-language question, not just keyword matches, so a phrase like the invoice from Sarah last month works even when you don't remember which account it landed in. We build AI Emaily. It won't replicate every classic Outlook feature covered above, but for searching everything you've connected in one pass, there's no scope menu to remember.