Solr cores not being created due to error in XML

[#1]

If the following error shows up when you are trying to create a solr core:

Unable to create core [tweets_shard1_replica1] Caused by: XML document structures must start and end within the same entity.

How do you get past this issue?

[#2 · Accepted solution]

You must verify that the solrconfig.xml has valid XML format and isn't missing entities.

You can use this website to validate the XML : XML Validator

You can also get a fresh copy of the solrconfig file from github if you have modified the original and don't have a backup.

solrconfig.xml