Outlook is Using an Old Copy of your Outlook Data File (OST) Error

Summary: When the Outlook OST file becomes inaccessible, an error message, such as Outlook is using an old copy of your Offline Folder file (.ost) is displayed. This error indicates a problem with the OST file that may be caused due to issues with an Outlook email client, Windows OS, mailbox synchronization, or OST corruption. In this guide, we discussed various solutions that can help you resolve the error and get back access to your mailbox items without losing any mailbox items.

OST or Offline Storage Table is an Outlook data file that stores a synchronized copy of all the mailbox items on local storage. Thus, it allows users to access their mail items even when the system is offline. For the most part, the OST file is quite reliable. However, it may get damaged due to various reasons, such as:

  1. Hardware or software issues
  2. Abrupt system shutdown or power outage
  3. Force close Outlook
  4. Virus or malware intrusion
  5. Problem with Outlook application or Windows OS

When OST gets damaged, mailbox synchronization stops and the user fails to access the mailbox items, such as emails, contacts, & attachments, even when the system is connected to the internet. In such cases, you may encounter error messages, such as,

Outlook is using an old copy of your Offline Folder file (.ost). Exit Outlook, delete the .ost file, and restart Outlook. A new file will be automatically created the next time you initiate a send/receive.

Outlook is Using an Old Copy of your Outlook Data File (OST) Error

Methods to Resolve Outlook is Using an Old Copy of your Outlook Data File (.ost) Error

Below we have discussed a few methods that may help you fix the problem with the OST file and resolve the OST file error. If these methods do not help, you can always use an OST to PST converter software such as Stellar Converter for OST. You can read more about the software in Method 3.

Method 1: Delete OST File

One method to fix this error is displayed in the error message. It says to delete .ost file and restart Outlook. This recreates the OST file and hence, provides access to your mail items. However, this may lead to a data loss situation.

If the error message appeared before OST synchronization, then any changes, mails, notes, or calendar items created or drafted in Outlook will be lost when you delete the OST file. To avoid this, backup your current OST file before deleting it from its default location. The OST location may vary based on the Windows OS version.

  • Windows XP: C:\Documents and Settings\Local Settings\Application Data\Microsoft\Outlook
  • Windows 7 & Vista: C:\Users\ProfileName\AppData\Local\Microsoft\Outlook
  • Windows 8 & 8.1: C:\Users\ ProfileName \AppData\Local\Microsoft\Outlook
  • Windows 10: C:\Users \ProfileName \AppData\Local\Microsoft\Outlook

The steps are as follows,

  1. Close Outlook program and then navigate to OST file location based on Windows OS
  2. Find the problematic .OST file
  3. Copy the .OST file and save it on an external or different drive safely
  4. Now delete the .OST file and then start the Outlook

This recreates a new OST file that contains a synchronized copy of all mailbox items stored on the Exchange server. Check your mail items thoroughly. If you find mail items missing, you can follow the next method to repair your problematic OST file to restore the lost mail items.

Method 2: Repair OST File

Microsoft Outlook comes with an Outlook data file repair tool called Inbox Repair tool or SCANPST.EXE. This tool can help detect and fix problems with the OST file that may be causing the error Outlook is Using an Old Copy of your Outlook Data File (OST).

To repair the OST file with the SCANPST.EXE tool, follow these steps,

  • Close Outlook and navigate to the following location based on Outlook and Windows version installed on your system:

Outlook 2016/2019

  • 32-bit Outlook: C:\Program Files (x86)\Microsoft Office\Office16\
  • 64-bit Outlook: C:\Program Files\Microsoft Office\Office16\

Outlook 2013

  • 32-bit Outlook: C:\Program Files (x86)\Microsoft Office\Office15\
  • 64-bit Outlook: C:\Program Files\Microsoft Office\Office15\

Outlook 2010

  • 32-bit Outlook: C:\Program Files (x86)\Microsoft Office\Office14\
  • 64-bit Outlook: C:\Program Files\Microsoft Office\Office14\

Outlook 2007

  • 32-bit Windows: C:\Program Files (x86)\Microsoft Office\Office12\
  • 64-bit Windows: C:\Program Files\Microsoft Office\Office12\
  • Then find and run the SCANPST.EXE tool
  • Click on ‘Browse’ to select the problematic OST file and click ‘Start’
  • The scanpst tool will scan the corrupt file and displays the ‘errors were found…’ message
  • Click on the ‘Make a backup of scanned file before repairing’ checkbox and then click ‘Repair’
  • After repair, you can copy the OST file back to its original location and open the Outlook

If Outlook opens, backup your lost mail items or exports them to a PST file. Then recreate the OST file by following Method 1.

Method 3: Use OST to PST Converter

When manual methods fail to fix Outlook is using an old copy of your Outlook Data file (.ost) error or lead to loss of mailbox items, you can rely on an OST to PST converter software, such as Stellar Converter for OST. This intuitive and easy-to-use tool scans inaccessible OST files and recovers all mailbox items, such as emails, attachments, contacts, calendar, tasks, etc. into an Outlook importable PST file. After recovery, this PST file can be directly imported into any MS Outlook profile.

The software is equipped with easy-to-use GUI, offers preview of recovered mail items, and features advanced search options to locate and export desired mail items to PST. It is one of the most reliable, fast, and secure ways to resolve various OST related Outlook errors without data loss.


The Outlook is using an old copy of your Outlook Data file (.ost) error can disrupt your Outlook account and lead to loss of mail items. If you have encountered this error message while accessing your Outlook account, you can fix it by simply deleting the problematic OST file. However, this can lead to data loss. Alternatively, you may attempt to repair the OST file by using the Inbox Repair tool. All these methods are discussed in this post to help you resolve the ‘Outlook is using an old copy of your Outlook Data file (.ost)’ error.

But when the OST is damaged beyond repair and OST recreation leads to loss of mail items, you can use an OST to PST converter software as discussed in this post. The software helps you to extract mail items from damaged OST files and save them to an Outlook importable PST format without data loss.