--- title: Outlook is using an old copy of your Outlook data file (.ost). Exit Outlook, delete the file... How to.. description: issue with Outlook where it's running an outdated copy of its Offline Outlook Data File (OST). image: https://newport-solutions.com/hubfs/AI-Generated%20Media/Images/An%20image%20of%20a%20computer%20screen%20showing%20an%20error%20message%20in%20Microsoft%20Outlook%20regarding%20using%20an%20old%20copy%20of%20the%20Outlook%20data%20file.jpeg --- [Skip to the main content.](https://newport-solutions.com/blog/outlook-is-using-an-old-copy-of-your-outlook-data-file-.ost.-exit-outlook-delete-the-file...-how-to#main-content) [![](https://newport-solutions.com/hubfs/Newport%20logo%20no%20background.svg)](https://newport-solutions.com) [![](https://newport-solutions.com/hubfs/Newport%20logo%20no%20background.svg)](https://newport-solutions.com) - Services - [IT Support](https://newport-solutions.com/it-support) - [Co-Managed IT](https://newport-solutions.com/it-support-co-managed) - [Cybersecurity](https://newport-solutions.com/cybersecurity-services) - [Backup & Recovery](https://newport-solutions.com/bdr) - [VoIP Phones](https://newport-solutions.com/voip-phones) - Industries - [Small Business](https://newport-solutions.com/it-support-for-smb-in-orange-county) - [Law Firms](https://newport-solutions.com/it-support-law-firms-orange-county) - [Manufacturing](https://newport-solutions.com/it-support-for-manufacturers-in-orange-county-newport-solutions) - [Real Estate](https://newport-solutions.com/it-support-for-commerical-real-estate-in-orange-county) - [About](https://newport-solutions.com/about-us) - [Contact Us](https://newport-solutions.com/contact) - [Store](https://newport-solutions-inc.square.site/) - [Blog](https://newport-solutions.com/blog) - [Resources](https://newport-solutions.com/resources) Search [![(714) 988-4194](https://no-cache.hubspot.com/cta/default/43983141/interactive-190851691842.png)](https://newport-solutions.com/hs/cta/wi/redirect?encryptedPayload=AVxigLLs1Saj87Fi981HnYTVQYwxP9y7kuQvwhozIQ%2BeGREgUpvhKsmbqfGFDnKJpAgt0yg5C9GjGLPzkYGnoejPrXAhWbTVK%2F5km7%2BoPnhbq0euF1eb64cm5fEv4ww6vFiGxxz4WJXrUuXceLpqay1UZHsD25aLmi%2FGqNw2FNZlF%2B0LXeOwoVhcvQA%3D&webInteractiveContentId=190851691842&portalId=43983141) Toggle Menu Search Toggle Menu [![(714) 988-4194](https://no-cache.hubspot.com/cta/default/43983141/interactive-190851691842.png)](https://newport-solutions.com/hs/cta/wi/redirect?encryptedPayload=AVxigLLs1Saj87Fi981HnYTVQYwxP9y7kuQvwhozIQ%2BeGREgUpvhKsmbqfGFDnKJpAgt0yg5C9GjGLPzkYGnoejPrXAhWbTVK%2F5km7%2BoPnhbq0euF1eb64cm5fEv4ww6vFiGxxz4WJXrUuXceLpqay1UZHsD25aLmi%2FGqNw2FNZlF%2B0LXeOwoVhcvQA%3D&webInteractiveContentId=190851691842&portalId=43983141) - Services - [IT Support](https://newport-solutions.com/it-support) - [Co-Managed IT](https://newport-solutions.com/it-support-co-managed) - [Cybersecurity](https://newport-solutions.com/cybersecurity-services) - [Backup & Recovery](https://newport-solutions.com/bdr) - [VoIP Phones](https://newport-solutions.com/voip-phones) - Industries - [Small Business](https://newport-solutions.com/it-support-for-smb-in-orange-county) - [Law Firms](https://newport-solutions.com/it-support-law-firms-orange-county) - [Manufacturing](https://newport-solutions.com/it-support-for-manufacturers-in-orange-county-newport-solutions) - [Real Estate](https://newport-solutions.com/it-support-for-commerical-real-estate-in-orange-county) - [About](https://newport-solutions.com/about-us) - [Contact Us](https://newport-solutions.com/contact) - [Store](https://newport-solutions-inc.square.site/) - [Blog](https://newport-solutions.com/blog) - [Resources](https://newport-solutions.com/resources) Schedule an Intro Call with Newport Solutions to discuss your business IT support and cybersecurity needs 1 min read # Outlook is using an old copy of your Outlook data file (.ost). Exit Outlook, delete the file... How to.. [Jeff](https://newport-solutions.com/blog/author/jeff) : June 27, 2024 Have you ever opened up your former or spare laptop, and Outlook does function like it used to?  If you receive an error that your Outlook Data file is using an old copy, here is the simple solution.  Of course, if you are a managed client, just contact our Help Desk and we will take care of this for you.    ![Old Outlook Data File Copy ...](https://newport-solutions.com/hs-fs/hubfs/undefined.jpeg?width=639&height=98&name=undefined.jpeg) It sounds like you're encountering an issue with Outlook where it's running an outdated copy of its Offline Outlook Data File (OST). Here’s a step-by-step guide on how to resolve this issue: 1. **Exit Outlook**: Close Microsoft Outlook completely. 2. **Delete the OST file**: - Navigate to the location where Outlook stores its OST files. Typically, this is in a path like `C:\Users\YOUR_username\AppData\Local\Microsoft\Outlook`. - Look for the OST file corresponding to your Outlook profile. The file names usually include your profile name or a unique identifier. - **Note**: Deleting the OST file will not delete your emails or data permanently, as it’s a cached copy of your mailbox stored locally. 3. **Reopen Outlook**: After deleting the OST file, reopen Microsoft Outlook. - Outlook will automatically recreate the OST file based on the latest data from your Exchange server or Office 365 mailbox. - This process might take some time depending on the size of your mailbox and the speed of your internet connection. 4. **Allow synchronization**: Once Outlook reopens, it will start synchronizing your emails, contacts, and other data from the server to the new OST file. 5. **Check for errors**: If Outlook encounters any errors during synchronization, it may prompt you with error messages or warnings. Follow any on-screen instructions to resolve these issues. By deleting the old OST file and allowing Outlook to recreate it, you should resolve the issue of Outlook running an old copy of the OST file. This ensures that your Outlook data is up-to-date and synchronized with your Exchange server or Office 365 mailbox. If you need assistance for your office staff, in and around Orange County, CA, please contact us to find out how we can be your outsourced managed IT department.  - [Tweet](https://twitter.com/share) [![How to Stop Outlook from Creating Reminders for Calendar Events (A Simple How-To Guide)](https://newport-solutions.com/hubfs/undefined.png)](https://newport-solutions.com/blog/how-to-stop-outlook-from-creating-reminders-for-calendar-events-a-simple-how-to-guide) 1 min read #### [How to Stop Outlook from Creating Reminders for Calendar Events (A Simple How-To Guide)](https://newport-solutions.com/blog/how-to-stop-outlook-from-creating-reminders-for-calendar-events-a-simple-how-to-guide) [Jeff](https://newport-solutions.com/blog/author/jeff) : Jan 22, 2026, 6:30:01 AM Outlook calendar reminders are helpful—until they aren’t. 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[Microsoft](https://newport-solutions.com/blog/tag/microsoft) [Read More](https://newport-solutions.com/blog/10-tips-to-get-the-most-out-of-your-microsoft-365-apps) [![How to Find Important Business Emails Hidden Behind Marketing Noise](https://newport-solutions.com/hubfs/generated-image-1.png)](https://newport-solutions.com/blog/how-to-find-important-business-emails-hidden-behind-marketing-noise) 1 min read #### [How to Find Important Business Emails Hidden Behind Marketing Noise](https://newport-solutions.com/blog/how-to-find-important-business-emails-hidden-behind-marketing-noise) [Chelsea](https://newport-solutions.com/blog/author/chelsea) : Apr 22, 2026, 9:30:00 AM As a busy Orange County business professional, you've probably experienced this frustrating scenario: You're searching for an important email from a... 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Exit Outlook, delete the file... How to..", "image" : [ "https://newport-solutions.com/hubfs/AI-Generated%20Media/Images/An%20image%20of%20a%20computer%20screen%20showing%20an%20error%20message%20in%20Microsoft%20Outlook%20regarding%20using%20an%20old%20copy%20of%20the%20Outlook%20data%20file.jpeg" ], "mainEntityOfPage" : { "@id" : "https://newport-solutions.com/blog/outlook-is-using-an-old-copy-of-your-outlook-data-file-.ost.-exit-outlook-delete-the-file...-how-to", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://newport-solutions.com/hubfs/Newport%20logo%20no%20background.svg" }, "name" : "Newport Solutions Inc." } } ``` ```json { "@context" : "https://schema.org", "@type" : "LocalBusiness", "address" : { "@type" : "PostalAddress", "addressLocality" : "Huntington Beach", "addressRegion" : "CA", "postalCode" : "92649", "streetAddress" : "5200 Warner Ave #203" }, "email" : "inquiry@newport-solutions.com", "name" : "Newport Solutions Inc", "telePhone" : "714-660-1811", "url" : "newport-solutions.com" } ```