How to fix Auto Archiving not working?

Hi Mark Chiasson,

Thank you for reaching out. Based on the issue you've described, it sounds like the PST file you're seeing — currently only 761 KB — is essentially empty, which is likely due to no messages meeting the archive criteria that were configured. May I know the process of creating that archive file?

Here’s a breakdown of what’s likely happening and how to address it:

Why the PST is only 761 KB
When Outlook creates a new archive file, it generates a blank PST that includes internal overhead and indexing data. Even without any emails being moved, this file will typically appear as a few hundred kilobytes. If no items match the archive settings (such as the "older than" date), nothing is exported, and the PST remains empty.

Common Causes

1,Empty Archive Range: Outlook’s Archive feature only moves emails older than a specified date. If that date is more recent than the actual message dates, nothing will be archived.

2,One-Sided Date Filtering: Outlook’s built-in archive doesn’t allow for a custom date range — only messages older than a single date are considered.

We can try using the Import/Export Wizard

To export emails within a specific date range (e.g., January to March 2025), follow these steps:

1. In Outlook, go to File > Open & Export > Import/Export
2. Choose Export to a file > Outlook Data File (.pst) and click Next
3. Select the desired mailbox or folder, then click Filter
4. Go to the Advanced tab and add two criteria:
   • Received on or after → [Start Date]
   • Received on or before → [End Date]
5. Click OK, select the PST save location, then click Finish

This method ensures only emails that fall within the specified date range are included in the PST.

Please consider about the issue with storing PST files in OneDrive. PSTs are not designed for cloud syncing, and OneDrive may constantly try to re-sync the entire file each time Outlook accesses it. This can cause sync conflicts, performance issues, or even data corruption.

If you’re using Microsoft 365, a better long-term solution is to enable the Online Archive feature, which automatically offloads older emails to an archive mailbox — all managed within Outlook and Exchange Online, with no need for PST files or manual backups. Let us know if you'd like help setting up an Online Archive or if you have any questions about the export process.

Best Regards,

Andy-Hu - MSFT | Microsoft Community Support Specialist