Error code
Blizzard BLZBNTAGT00000840
BLIZZARDBLZBNTAGT00000840
Game/Platform Error· An error code shown by a game or gaming platform/launcher.
What it means
Something went wrong with a game file and the update cannot proceed..
How to fix it
- Run Battle.net as administrator.
- Disable third-party add-on managers.
- Use Scan and Repair on the affected game.
- Verify the Secondary Logon service is enabled in Windows Services.
- Configure antivirus exceptions for Blizzard.
- Reinstall the game as a last resort.
Not affiliated with Blizzard. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.
More Blizzard codes
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- BLZ51914003The WoW game client was immediately disconnected after attempting to connect to a realm.
- BLZ51934200World of Warcraft shows "There are currently no servers available" — common on patch days.
- BLZBNTAGT0000084BThe Battle.net Update Agent could not modify the necessary game files on disk.
- BLZBNTAGT000008A4The Battle.net desktop app is unable to download a file required for installation or patching.
- BLZBNTAGT000008FCThere is a conflict with one or more programs or services on the system.
- BLZBNTAGT00000960The Battle.net launcher failed to save or apply update files during patching.
- BLZBNTAGT00000BB8The Battle.net Update Agent failed to download or write new update data.
- BLZBNTAGT00000BCEA game patch failed because the downloaded patch data is corrupt or invalid.
- BLZBNTAGT00001389The Battle.net desktop app cannot download a file needed to install or update a game.
- BLZBNTBGS00000033The Battle.net account does not have a Call of Duty license linked to it.