The Battle.net Update Agent couldn't modify necessary files on your hard drive. This usually happens when the required files are locked or in use by another program. Follow the steps below to resolve the issue.
Restart your computer to resolve problems caused by programs and services running in the background.
Run the repair tool to repair any damaged game files.
Update or temporarily uninstall any security programs, which may mistakenly identify the login module as a security threat.
Close all other applications to resolve software conflicts and free up resources.
Run the Blizzard Battle.net desktop app in Administrator Mode to address many installation, patching, networking, and start-up errors.
Tried everything here?
If the steps above did not resolve your problem, visit our Technical Support forum or contact us.