Symptoms

Upgrading a Confluence instance that is connected to Crowd to Confluence version 3.1.x returns this error:

You did not enter a valid username and password for a Confluence administrator.

Cause

Confluence 3.1.x requires a version 2 license key, for this it requires admin user's username and password to complete the procedure. Unfortunately it does not honor Crowd Confluence Admin user.

Workaround

1. Setup a new instance of Confluence 3.1.x that is not connected to Crowd and use a version 2 license key.
2. Edit <confluence home>/confluence.cfg.xml.
3. Copy confluence.license.message and confluence.license.hash from the new instance and copy these across to the target instance's confluence.cfg.xml where you want to upgrade.
4. Redo the upgrade process.

Resolution

The problem is corrected in Confluence 3.2. See Cannot upgrade to Confluence 3.1.x when using Crowd integration.