My migration to SharePoint 2010 from SharePoint 2007 went mostly smoothly. One exception to that statement was getting my data connections in InfoPath Forms Services to work again.
I came across this error today:
Current configuration settings prohibit embedding username and password in the database connection string
A quick check of the InfoPath Form Services settings in Central Administration>General Application Settings>InfoPath Form Services>Configure InfoPath Form Services resolved my problem…
I needed to allow:
Embedded SQL authentication
User form templates to use authentication information contained in data connection files
Cross-domain data access for user form templates that use connection settings in a data connection file
Saving those settings got my data connections working again!