SYMPTOM:
When attempting to connect to a project source in Strategy Developer 10.x after an upgrade, the following error message appears.

Sample Code/Error
Different password is used by another connected data source. If you are sure that this is a new password and want to use this new password to login, please disconnect that data source.
CAUSE:
One possible cause is that the project source became inconsistent.
ACTION:
Open Strategy Desktop and within the project source in question, right click and select delete as shown in the image below:

Close and re-open Strategy Desktop to recreate the three-tier project source using the correct username and password.