Outlook data file has reached maximum size

Karen Langsley 20 Reputation points
2026-07-07T15:32:56.6333333+00:00

I attempted to remove some items in my archive file but get the same error message.

Outlook | Windows | Classic Outlook for Windows | For business
Answer accepted by question author
Anonymous
2026-07-07T17:29:05.5766667+00:00

Hi Karen,

Thank you for reaching out and providing details about the issue you're experiencing.  

This issue usually occurs because deleting items from an Outlook archive does not immediately reduce the size of the actual data file. Even after items are removed, the archive (.pst) file may remain at or near its maximum size until it is manually compacted. 

For reference: Reduce the size of your mailbox and Outlook Data Files (.pst and .ost) | Microsoft Support 

Please try the following steps: 

1/ Empty Deleted Items within the Archive 

In Classic Outlook: 

  • Expand the Archive (or archive .pst) in the folder list. 
  • Locate the Deleted Items folder within that archive. 
  • Right-click Deleted Items and select Empty Folder. 
  • If you are deleting individual items, use Shift + Delete to permanently remove them. 

You may also want to check for messages with large attachments. To find large emails, use Outlook Search with the following query: 

messagesize:>5 mb 

Review the search results and delete or move large messages as appropriate to free up space in the data file. 

 

2/ Compact the archive PST manually ( recommended ) 

After deleting items, manually compact the archive file: 

  • Go to File > Account Settings > Account Settings. 
  • Select the Data Files tab. 
  • Highlight the archive .pst file. 
  • Click Settings. 

Note: If you are using an Exchange account, select the Advanced tab and then choose Outlook Data File Settings. 

  • Click Compact Now. 
  • Allow the process to complete. 
  • Restart Outlook. 

 3

If the issue persists: 

If the archive file is already very close to the maximum size limit, you may need to create a new archive PST and move older content into it. 

To create a new archive file: 

  • Go to File > Account Settings > Account Settings. 
  • Open the Data Files tab. 
  • Click Add. 
  • Create a new PST file (for example, Archive_2020_and_older.pst). 
  • Move older folders or date ranges from the existing archive into the new PST file. 
  • Compact the original archive again after the move is complete. 

I hope this helps fix the issue. If you continue to receive the same error after completing these steps, please let me know and we will be happy to assist further. 

Thank you for your patience and understanding. 

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  1. Rizwana 195 Reputation points
    2026-07-07T16:52:06.57+00:00

    This error occurs when your Outlook data file (PST/Archive) has reached its maximum size limit, which prevents further actions like deleting or moving items.

    Even if you try to delete emails, Outlook may still show the same error because the file needs to be compacted to actually free space.

    Here are the steps to fix the issue:

    1. Empty Deleted Items Folder
    • Right-click "Deleted Items"
    • Click "Empty Folder"

    Also check:

    • Junk Email folder
    • Large attachments in Inbox/Sent Items
    1. Manually Delete Large Emails

    Sort emails by size:

    • Go to Inbox → View → Sort by Size
    • Delete emails with large attachments
    1. Compact the Outlook Data File (IMPORTANT)

    Deleting emails does NOT reduce file size until you compact it.

    Steps:

    • File → Account Settings → Account Settings
    • Go to "Data Files" tab
    • Select your PST/Archive file
    • Click "Settings" → "Compact Now"

    This will actually reduce the file size.

    1. Create a New Archive File

    If the file is already at limit:

    • File → Account Settings → Data Files → Add
    • Create a new PST file
    • Move old emails to the new file
    1. Check PST File Size Limits
    • Older Outlook (ANSI PST): ~2GB limit
    • Newer Outlook (Unicode PST): ~50GB default

    If needed, increase limit via Registry (advanced users only)

    1. Run Inbox Repair Tool (SCANPST)

    If file is stuck:

    • Close Outlook
    • Run SCANPST.exe
    • Scan and repair your PST file
    1. For Storage Management (Second Question)

    To clear storage:

    • Empty Deleted Items & Junk
    • Remove large attachments
    • Archive old emails
    • Use "Mailbox Cleanup" tool: File → Tools → Mailbox Cleanup

    ✅ Summary:

    This issue happens because the PST file is full AND not compacted.

    Deleting emails + compacting the file OR creating a new archive resolves the problem in most cases.

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