How to Fix Outlook Error 0x8004010F When Your Data File Cannot Be Accessed

Error 0x8004010F, with the message “Outlook data file cannot be accessed,” usually appears the moment you press Send and Receive. Outlook knows where your mail should go, but it cannot open the PST or OST file that stores it. This often happens after you move a data file, restore a backup, change a profile, or upgrade Outlook.

Quick Answer

Error 0x8004010F means Outlook cannot find or open the data file linked to your account. Open Account Settings, check the Data Files tab, and confirm the file location is correct. If the path is wrong, point Outlook to the real file or create a new profile and set the correct delivery location, which fixes the error in most cases.

What Causes Outlook Data File Cannot Be Accessed?

Every Outlook account delivers mail into a data file. POP3 accounts normally use a PST file stored on your computer, while IMAP and Exchange accounts use an OST file that mirrors the server. When Outlook cannot reach that file at the recorded path, sending and receiving stop.

The most common triggers are easy to understand. The file was moved to a new folder or a new drive, the profile was copied from another computer, an upgrade changed default locations, or the profile became corrupted. Antivirus scans, forced shutdowns, and a full disk can also damage a file or lock it so Outlook cannot open it.

• Moved or renamed file: Outlook still looks in the old folder.
• Corrupted profile: The account points to a location that no longer exists.
• Damaged PST or OST: The file exists, but Outlook cannot read its structure.
• Permission problems: The file sits in a folder your Windows account cannot fully access.
• File stored on a network or removable drive: The drive is disconnected or too slow to respond.

Step 1: Find Where Your Data File Should Be

Before changing anything, confirm the recorded path and whether a file actually exists there.

1. In Outlook, go to File > Account Settings > Account Settings.
2. Open the Data Files tab and note the location shown for your account.
3. Select the file entry and choose Open File Location if Outlook offers it.
4. If the folder does not open, copy the path into File Explorer and check it manually.
5. Look for files ending in .pst or .ost and note their sizes. A file with a realistic size usually means your data is still present.

If the file is missing from that folder but exists somewhere else, do not move things at random yet. Finish the checks below first so you change the setting, not the data, whenever possible.

Step 2: Correct the Delivery Location for a POP3 Account

For POP3 accounts, Outlook must be told exactly which data file receives new mail. A wrong delivery folder is a classic cause of this error.

1. Go to File > Account Settings > Account Settings and select the Email tab.
2. Select your POP3 account and choose Change Folder at the bottom of the window.
3. Select the correct Inbox inside your existing PST file.
4. If the correct file is not listed, choose New Outlook Data File, create one in a simple local folder, and select its Inbox.
5. Click OK, close the settings, restart Outlook, and press Send/Receive.

If you had to create a new file, your old mail stays in the old PST. You can open that file later through File > Open & Export > Open Outlook Data File and move messages across carefully. If the new delivery location needs a clean profile as well, follow the principles in our related guide on resolving Outlook profile creation errors before you rebuild anything.

Step 3: Create a New Outlook Profile and Point It to the File

When the delivery setting will not save, or the error appears on an IMAP or Exchange account, a fresh profile is often the cleanest repair.

1. Close Outlook completely and open Control Panel.
2. Search for Mail and open Mail (Microsoft Outlook).
3. Choose Show Profiles, then Add, and name the new profile clearly.
4. Add your email account with your provider’s correct server settings.
5. For a POP3 account, when prompted for the data file, select the existing PST file you found in Step 1.
6. Set the new profile as the default and start Outlook to test sending and receiving.

Keep the old profile untouched until the new one has worked for a few days. That way, if something is missing, you still have a path back to the original setup. Microsoft describes the same profile approach in its official guidance on repairing an Outlook profile to fix connection problems.

Step 4: Repair a Damaged PST File With ScanPST

If the file exists at the correct path but Outlook still cannot open it, the file itself may be damaged. Outlook includes a repair tool called the Inbox Repair Tool, or ScanPST.exe.

1. Close Outlook so the file is not in use.
2. Find ScanPST.exe in your Office installation folder. Its location depends on your Office version and whether it is 32-bit or 64-bit.
3. Run the tool, browse to your PST file, and choose Start to scan it.
4. If errors are found, make sure the backup option is ticked, then choose Repair.
5. Open Outlook again and test. You may need to run the scan more than once until no major errors are reported.

For an OST file, repair is usually unnecessary. Because an OST is a copy of server data, you can close Outlook, rename the OST with a .old ending, and restart Outlook so it rebuilds a fresh copy from the server. Only do this for IMAP or Exchange accounts, never for a POP3 PST that holds your only copy of mail.

Step 5: Check Permissions and File Location

A file in the wrong place can fail even when it is healthy. Keep data files on a local drive in a folder you own.

1. Right-click the data file, choose Properties, and make sure Read-only is not ticked.
2. Check the Security tab and confirm your Windows user has Modify permission.
3. Avoid storing active PST files inside cloud sync folders or on USB drives, which can lock or delay access.
4. Make sure your disk is not completely full, because Outlook needs working space to open and write to the file.

Common Mistakes to Avoid

• Deleting the data file: Deleting a PST can delete your only copy of POP3 mail. Always copy it to a safe backup first.
• Renaming an OST and a PST the same way: Rebuilding works for server-synced OST files, not for local-only PST data.
• Importing the whole PST repeatedly: Repeated imports create duplicates. Open the file instead and move only what you need.
• Running ScanPST while Outlook is open: The tool needs exclusive access, so close Outlook and any sync tools first.
• Storing the file on a network share: Microsoft does not support active PST files over a network, and the practice commonly causes this exact error.

Conclusion

Error 0x8004010F is Outlook telling you it cannot reach the file where your mail lives. Confirm the recorded path, correct the delivery folder for POP3 accounts, test with a new profile, and repair a damaged PST with ScanPST while rebuilding only server-synced OST files. Work slowly, back up the data file first, and your mail will normally be sending and receiving again without any loss.

Frequently Asked Questions

Does error 0x8004010F mean my emails are deleted?

Usually not. In most cases the messages are safe inside the PST or on the mail server, and Outlook simply cannot open the file at the recorded location. Fixing the path or profile reconnects Outlook to the same data.

What is the difference between a PST and an OST file?

A PST is a local data file most often used by POP3 accounts and archives, and it may hold the only copy of your mail. An OST is an offline copy of a server mailbox used by IMAP and Exchange accounts, so it can be rebuilt from the server.

Can I just move the data file back to the old folder?

Yes, if you know the exact original path and Outlook is closed, moving the file back can be the fastest fix. Copy rather than move it until Outlook opens it successfully, so you always keep a backup.

Why does this error appear after moving Outlook to a new PC?

The copied profile still points to the old computer’s folder path or username. Creating a new profile on the new PC and pointing it to the copied PST file corrects the path and removes the error.

Should I run ScanPST on an OST file?

It is rarely the best choice. For IMAP and Exchange accounts, renaming the OST and letting Outlook rebuild it from the server is cleaner and safer. Reserve ScanPST mainly for PST files that hold local data.