Outlook Error 0x8004010F ("Data File Cannot Be Accessed")? Rebuild the Profile, Not the PST

Outlook send/receive fails with: “Task ‘Sending’ reported error (0x8004010F): ‘Outlook data file cannot be accessed.’”

Why PST-repair tools are the wrong turn: the top results push scanpst.exe or paid “PST repair” utilities. But 0x8004010F is almost always a corrupted Outlook profile — the profile’s pointer to your data file is broken — not damage inside the data file. Repairing the PST does nothing for a broken profile pointer. The documented fix is a fresh profile aimed at your existing data file.

Fix 1: Find your current default data file

1. Control Panel → Mail (Microsoft Outlook) → Show Profiles → Properties → Data Files.
2. Note the default data file and its location (e.g. …\Documents\Outlook Files\you.pst or …\AppData\Local\Microsoft\Outlook\you.ost). You’ll point the new profile at this.

Fix 2: Create a new mail profile

1. In Mail → Show Profiles, click Add, name it (e.g. Outlook2).
2. Add your email account. For an Exchange/365 account it rebuilds the OST automatically; for a POP/PST account, when prompted use the existing data file from Fix 1 (don’t create a duplicate).
3. Set “Always use this profile” to the new one, click OK.
4. Open Outlook on the new profile and run Send/Receive — the error is gone.

Fix 3: If it’s a POP account, re-point the delivery location

POP3 accounts throw 0x8004010F when the “deliver to” PST is missing or moved:

• File → Account Settings → Data Files — make sure the intended PST is listed and Set as Default.
• If the PST moved, add it from its real path, set default, restart Outlook.

Fix 4: Repair the data file only if needed

If, after a fresh profile, a specific folder still errors, then run scanpst.exe (the Inbox Repair Tool, in the Office install folder) against that file — this is the right time for it, not before.

FAQ

Will I lose mail making a new profile? No — for Exchange/365 it re-downloads from the server; for POP, you reuse the same PST. Your mail is intact.

Why did it start out of nowhere? A moved/renamed data file, a OneDrive-redirected Documents folder, or a profile glitch breaks the pointer. The new profile re-establishes it.

It’s an endless password prompt, not 0x8004010F. Different issue — see Outlook keeps asking for your password.

Sources: Microsoft Learn — Error 0x8004010F when sending or receiving email in Outlook