New Outlook Online Archive Settings: Location and Practical Limits

The new Outlook for Windows and the web version offer an Online Archive feature to store older emails without cluttering your primary mailbox. This archive is a separate mailbox that appears below your main Inbox folder list. Many users need to know exactly where to find the archive settings and what storage limits apply. This article explains where the Online Archive settings are located in the new Outlook interface, the practical storage and retention limits, and what happens when you approach those limits.

What the Online Archive Feature Does and Why It Exists

The Online Archive in the new Outlook is a cloud-based storage location for older messages. It is part of the Exchange Online mailbox plan for Microsoft 365 Business and Enterprise subscriptions. The archive mailbox appears as a separate folder set under your primary mailbox in the folder pane. You can move items manually or set policies to move items older than a specified number of days.

The purpose of the archive is to reduce the size of your primary mailbox. Many organizations set a quota on the primary mailbox of 50 GB or 100 GB. Moving aged items to the archive helps you stay under that quota without deleting anything. The archive is fully searchable in the new Outlook, so you can find archived messages the same way you search your Inbox.

Before you can use the archive, your Microsoft 365 admin must enable it for your account. This is done in the Exchange admin center under recipient mailboxes. Once enabled, the archive appears automatically in the new Outlook after a short sync. No additional add-ins or downloads are needed.

Where to Find Online Archive Settings in the New Outlook

The settings for the Online Archive are located in two main areas: the folder pane for viewing the archive and the Settings panel for configuring automatic archiving rules.

Viewing the Archive Folder

After your admin enables the archive, the Online Archive appears in the folder pane on the left side of the new Outlook window. It is listed below your primary mailbox with a label like “Online Archive – yourname@domain.com.” Click the expand arrow next to it to see the folder structure. The default folders are Inbox, Sent Items, Deleted Items, and any custom folders you create.

Configuring Archive Settings

1. Open the Settings panel
   Click the gear icon in the upper-right corner of the new Outlook window. Alternatively, press Ctrl+Comma.
2. Navigate to Mail > Automatic Processing
   In the Settings panel, click Mail on the left. Then click Automatic Processing on the right.
3. Select Archive
   Under Automatic Processing, click Archive. This page shows options for moving items to the archive automatically and for manually archiving selected folders.
4. Set the auto-archive policy
   Toggle the switch to enable automatic archiving. Choose the folder you want to apply the policy to. Set the number of days after which items are moved to the archive. The default is 365 days.
5. Apply the policy
   Click Save at the bottom of the panel. The rule will run daily and move qualifying items from the selected folder to the corresponding folder in the archive.

You can also manually move items. Right-click a folder in your primary mailbox and select Archive. This moves all items in that folder that are older than the retention setting to the archive. If no retention setting exists, the archive move uses the default of 365 days.

Practical Storage and Retention Limits of the Online Archive

The Online Archive has specific limits that affect how you use it. These limits are set by Microsoft and apply to all Microsoft 365 Business and Enterprise subscriptions that include Exchange Online Archiving.

Storage Capacity

Each archive mailbox has a default storage limit of 100 GB. This is the total space for all folders and items in the archive. There is no per-folder limit. When the archive reaches 90 GB, the mailbox owner receives a warning email from the system. At 100 GB, no new items can be moved or delivered to the archive. Items already in the archive remain accessible but cannot be added to.

Item Size Limit

Individual items moved to the archive cannot exceed 150 MB. This includes the message body and all attachments. If you try to move a larger item, the move fails and Outlook shows an error. The item stays in the primary mailbox.

Retention Policies

Retention policies control how long items stay in the archive before being deleted. These policies are set by your Exchange admin, not by you. Common retention periods are 1 year, 3 years, 5 years, or indefinite. To check your organization’s policy, contact your IT department. You cannot override the policy from the Outlook settings.

Number of Items

Microsoft does not publish a hard limit on the number of items in an archive mailbox. However, performance degrades when the archive contains more than one million items. Searching and folder navigation become noticeably slower. If you expect to archive a very large volume of email, consider creating separate archive folders for different years or projects to keep item counts manageable.

If the Online Archive Does Not Appear or Fails to Move Items

Archive Folder Is Missing from the Folder Pane

If you do not see the Online Archive listed below your primary mailbox, the feature is not enabled for your account. Contact your Microsoft 365 admin and ask them to enable the archive in the Exchange admin center. After they enable it, restart the new Outlook. The archive should appear within 30 minutes.

Items Fail to Move to Archive

When you try to move items manually or via a policy and the move fails, check the following:

• The archive storage is not full. Check the archive mailbox size by right-clicking the archive folder and selecting Properties. Look for the size display.
• The item is not larger than 150 MB. Check the size of the item by opening it and looking in the lower-right corner of the message window.
• The item does not have a retention hold that prevents moves. Some legal holds or litigation holds block archiving. Your admin can remove these holds if needed.

Archive Search Returns No Results

The new Outlook indexes archive mailboxes separately from the primary mailbox. If search does not find items in the archive, rebuild the search index. Go to Settings > General > Search. Click Rebuild Index. This process may take several hours for large archives.

Item	Primary Mailbox	Online Archive
Default storage limit	50 GB or 100 GB (plan dependent)	100 GB
Maximum item size	150 MB	150 MB
Retention control	User can set via Outlook rules	Admin sets via retention policies
Appears in folder pane	Always visible	Visible only when enabled by admin
Search index	Indexed by default	Indexed but requires separate rebuild

The Online Archive is a practical tool for managing mailbox size in the new Outlook. Locate the settings under Settings > Mail > Automatic Processing > Archive. Remember the 100 GB storage limit and the 150 MB per-item limit. If the archive does not appear or fails to move items, check with your admin for enablement and retention policies. For best performance, keep the archive item count below one million by organizing into subfolders by year.