By default Solr's ManifoldCF logging is set to info logging level. This is often too much information which can make it difficult to identify errors and warnings. Here are the steps to change the log level to a more appropriate level.
Edit the following file on the Solr box.
C:\Program Files (x86)\Ektron\Search2.0\ManifoldCF\core\properties.xml
Look for all places that are not commented out where value=”INFO” or "DEBUG." Change these to value=”WARN”. Restart process manager to implement the change.