Fix 0x8004010F: 'Outlook Data File Cannot Be Accessed'

If you encounter the error ‘0x8004010F Outlook data file cannot be accessed,’ there are several methods you can follow to fix the problem. These methods are suitable for Outlook 2021, 2019, 2016, 2013 and 2010.

1. Method 1: Verify the Default Data File and Profile

   Microsoft's documented starting point for this error is to confirm which data file your profile is actually pointing to, and whether it's the one you expect. This is worth doing before any destructive step.

   • Step 1: Open Account Settings
     • In Outlook, click the ‘File’ tab, then ‘Account Settings’ → ‘Account Settings’ again.
   • Step 2: Check the Data Files tab
     • Click the ‘Data Files’ tab and note which file is marked as the default for your account.
     • Click ‘Open File Location’ to confirm that file actually exists at that path.
   • Step 3: Check Show Profiles
     • In Control Panel > Mail > ‘Show Profiles’, confirm the profile you're using is the one associated with that data file, and that it's set as the one Outlook always uses (or that you're prompted to pick it).

   What this tells you

   If the default data file is missing, points to the wrong path, or the profile looks damaged, that matches Microsoft's documented cause for this error — move on to Method 2. If the file exists, is correctly referenced, and the profile looks fine, the cause is more likely one of the secondary issues below (permissions, add-ins, a temporary glitch).

2. Method 2: Create a New Outlook Profile

   If Method 1 shows the default data file is missing, misconfigured, or the profile itself looks damaged, creating a new Outlook profile is Microsoft's documented fix for this error in classic Outlook. Before you do: if there's any chance the current OST holds data that never synced to the server, preserve a copy of it first — this method creates a fresh data file, and the old one is not automatically kept.

   Creating a new Outlook profile is an effective way to resolve the ‘Outlook data file cannot be accessed’ error message. The error can be caused by a corrupted or damaged Outlook profile, so creating a new profile can help to fix the issue. When you create a new profile, you are essentially starting from scratch with Outlook, which can help to eliminate any existing issues with the old profile. By setting the new profile as the default, you ensure that Outlook uses the new profile instead of the old one. Adding your email account to the new profile ensures that you can continue to send and receive emails as normal.

   • Step 1: Open the Control Panel and find the Mail applet
     • Click on the ‘Start’ button in the bottom left corner of your screen and type ‘Control Panel’ in the search box.
     • In the Control Panel, ‘Mail’ (Microsoft Outlook 2016) option

       

   • Step 2: Add a new profile and name the profile
     • In the Mail Setup window, click on the ‘Show Profiles’ button. Then click on the ‘Add’ button to create a new profile.
     • In the ‘New Profile’ window, enter a name for the new profile and click ‘OK’

       

   • Step 3: Add an email account to the profile
     • In the ‘Add New Account’ window, the automatic method or ‘Manual setup or additional server types’.
     • Click ‘Next’ and enter the required information to set up the account.
   • Step 4: Set the new profile as the default
     • After you have added your email account to the new profile, go back to the ‘Mail’ applet in the Control Panel.
     • Click on the ‘Show Profiles’ button, select the new profile you just created, and make the profile default.

       

   • Step 5: Restart Outlook

     Close the Mail applet and open Outlook. The new profile should be active, and the ‘Outlook data file cannot be accessed’ error message should be resolved.

3. Quick check: Close and Restart Outlook

   The easiest and most effective way to fix the ‘Outlook data file cannot be accessed’ error is to simply close Outlook down and restart it. The method works by deleting any temporary files, processes, or services linked to Outlook, which may be responsible for the error. Stopping the Outlook process will also stop all the services and processes related to it. Restarting Outlook will start the program afresh without any residual processes or files.

   This method is also useful in fixing other Outlook-related issues, such as slow performance or freezing. It is a quick and easy way to troubleshoot common Outlook problems. Sometimes it’s a temporary glitch in the application that leads to the error. In such cases, closing and re-opening Outlook could fix the problem.

   • Step 1: Close Outlook on your computer
     • First, you need to close Outlook completely. If you have any open windows or dialogs in Outlook, close them all.
     • Click the ‘X’ button in the top right corner of each window or dialog or click ‘File’ > ’Exit’.
   • Step 2: End all Outlook related processes

     Sometimes, even after you close Outlook, the Outlook process may continue to run in the background.

     To make sure that the process is completely ended, follow these steps:

     • Open the Task Manager by pressing the Ctrl+Shift+Esc keys.
     • In the Task Manager, go to the ‘Processes’ tab and look for the ‘Outlook.exe’ process.
     • Select the process and click ‘End task’.

     After ending the Outlook process, wait for a few minutes before starting Outlook again. This ensures that any background processes or services related to Outlook are also stopped.

   • Step 3: Restart Outlook and verify email access

     Start Outlook again from your computer by clicking the shortcut on your desktop or by searching for it in the Start menu. Check if the error is resolved and that you are able to access your email messages

4. Quick check: Verify the Data File Location and Permissions

   Ensure the Outlook data file is in the right place on your computer. If the file was moved or deleted (either by mistake or by another program) then Outlook may not be able to locate it, and you will get the 0x8004010F: Outlook 365 data file cannot be accessed error. Verifying the location of the file and checking the permissions on the folder is a critical part of fixing the problem.

   • Step 1: Open Outlook and select Account Settings
     • To start Outlook, click on the Outlook shortcut on your desktop or search for it in the Start menu.
     • Click the ‘File’ tab at the top left-hand corner of the window.
     • In the File menu, click 'Account Settings' and again select 'Account Settings' from the dropdown list.

       

   • Step 2: Find the Outlook data file and check its location
     • In the Account Settings window, click the ‘Data Files’ tab.
     • Here you should see a list of all the data files that are tied to your Outlook profile.
     • Click ‘Open File Location’ and make sure that the path is correct and that the file is located in the folder where it is supposed to be.
     • If the file is not where Outlook expects it, don't just move it back blindly. For an Exchange or Microsoft 365 account, it's usually cleaner to let Outlook rebuild the OST from the server via a fresh profile (Method 2 above) than to manually relocate the old file. Manual relocation is more relevant for a POP/IMAP PST that is itself the authoritative local copy.

       

   • Step 3: Verify the file permissions of the file

     Check the file permissions to confirm you have permission to access the file.

     • Right-click on the folder that contains the data file, then choose ‘Properties’ from the drop-down list.
     • In the Properties window, go to the ‘Security’ tab and check that your user account has the correct permissions to access the file.
   • Step 4: Restart Your Outlook
     • After verifying the data file’s location and permissions, shut down and restart Outlook to determine whether the error message no longer appears.
     • If still there, try the next method to resolve the issue.
5. Quick check: Turn Off Conflicting Outlook Add-ins

   Add-ins are third-party programs that extend the functionality of Outlook. However, some Add-ins or plugins may conflict with other Add-ins or Outlook itself and can cause errors and issues. Disabling add-ins is a great way to troubleshoot the error message, ‘0x8004010F Outlook 2016 data file cannot be accessed’.

   Disabling add-ins is a useful way to determine if one of them is causing the Outlook data file access error. Faulty or old Add-ins can interfere with the normal running of Outlook, causing error messages, slow performance or Outlook freezing. You can turn off all Add-ins at once, and then determine which Add-in is causing the problem by starting Outlook in Safe Mode. This method is effective, simple, and will often save you time when troubleshooting. After you find the problematic Add-in, you can remove it or update it and fix the issue.

   • Step 1: Launch Outlook in Safe Mode

     First of all, you need to open Outlook in Safe Mode to disable any conflicting add-ins.

     • Press and hold the ‘Ctrl’ key and click on the Outlook shortcut on your desktop.
     • When prompted, click 'Yes' to boot into Safe Mode.
   • Step 2: In Options, go to the Add-ins section
     • When you open Outlook in Safe Mode, go to the ‘File’ tab in the top left corner of the window.
     • Click 'Options' in the File menu and then choose 'Add-ins' from the list of options.
   • Step 3: Disable Add-ins and Restart Outlook
     • And in the Add-ins window, you should see a list of all currently installed Add-ins in Outlook.
     • To disable the Add-in, deselect it in the options and click OK.
     • When you have disabled the Add-ins, close and re-open Outlook to check if the error message is gone.
     • Try this for each Add-in to find the incompatible one
     • If the error message still appears or the inbox is not updating automatically in Outlook, then you can try the next method to fix the problem.

       

6. When EdbMails OST to PST Converter Is Actually Required

   Use OST recovery only when the server-side mailbox genuinely cannot provide the data you need, the original profile cannot be restored, or the old OST contains local-only items that were never synchronized.

   If the mailbox/profile cannot be restored and required data exists only in the old OST, use the EdbMails OST to PST Converter to scan the preserved file, preview readable mailbox data, and export the required content to PST.

   • Preserve a copy of the old OST before recreating the Outlook profile or cache.
   • Scan and preview the readable folders/items before deciding what must be recovered.
   • Export the required data to PST or use a supported direct migration destination when appropriate.

   For the complete product procedure and screenshots, see the OST to PST conversion guide.