I have encountered the same problem Karl reported in the following ticket: https://issues.apache.org/jira/browse/SOLR-12798
Since the ticket is unresolved, is this still a problem with the latest MCF version? I get the following error when the Solr connector tries to delete documents: FATAL 2019-01-21T09:44:15,346 (Worker thread '6') - Error tossed: This Should not happen java.lang.RuntimeException: This Should not happen at org.apache.solr.client.solrj.impl.BinaryRequestWriter.getContentStreams(BinaryRequestWriter.java:67) ~[?:?] […] at org.apache.manifoldcf.agents.output.solr.HttpPoster$DeleteThread.run(HttpPoster.java:1366) ~[?:?] I'm just asking in case my preemptive patch is causing these problems. Erlend
