Getting all my emails in Outlook

Outlook 2019 (and newer) uses the Cached Exchange Mode setting called Mail to keep offline, which by default only syncs the most recent emails to your local OST file. To have Outlook download all emails, you need to adjust this setting.

Here’s how to fix it:

✅ Open Outlook 2019.

Go to the File menu (top-left corner).

Click Account Settings → Account Settings again.

In the Email tab, select your email account and click Change.

In the Offline Settings section, you’ll see a slider labeled:

“Mail to keep offline”

Move the slider all the way to the right to select All.

Click Next, then Finish.

Restart Outlook for the changes to take effect.

🔄 What Happens Next?
Outlook will now start syncing all emails from your Exchange mailbox to the local computer.

Depending on the size of your mailbox and network speed, this could take minutes to hours.

However, you will need to change the search parameters if you want to search on all the additional email. This happens because search in Outlook is powered by the Windows Search index, and by default, Outlook limits search results to “Recent Emails” unless you adjust the settings. Even though all your mail is now synced locally, Outlook’s search results may still only show the last 12 months (or less).

✅ Fix: Show All Mail in Search Results

1️⃣ Change Outlook Search Options

Open Outlook.

Go to File > Options > Search.

Under Results, find:

✅ “Improve search speed by limiting the number of results shown”

Uncheck this option.

Click OK and restart Outlook.

This tells Outlook to include all emails in search results.

2️⃣ Rebuild the Windows Search Index (if needed)

If older emails still don’t appear:

Go to Control Panel > Indexing Options.

Click Modify and ensure Microsoft Outlook is checked.

Back in the Indexing Options window, click Advanced → Rebuild.

This will rebuild the search index. It can take some time, especially if you have a large mailbox.

⏳ How Long Will It Take?

If your OST file is several GB, the rebuild might take hours (leave your PC running and Outlook open).

You can monitor progress in Indexing Options: it will say “Items remaining to index.”

⚡ Optional: Use “All Mailboxes” Search Scope

When searching in Outlook:

Click in the Search bar.

On the Search Tools tab, select All Mailboxes or All Outlook Items.
This ensures you’re searching beyond “Current Folder” or “Recent Emails.”