SOLR: no segments* file found

While playing around with one of my development SOLR installations (this time under Windows), I suddenly got a weird error message when feeding data to one of the fresh cores.

SEVERE: java.lang.RuntimeException: no segments* file found in\temp\solr\*\data\index: files:

Taking a look at the contents of the index\ directory, it was in fact empty. Seems weird, but my initial guess was that Lucene / SOLR would treat this as a new installation and create the files.

Turns out the issue is that it won’t – as long as the index directory exists, Lucene / SOLR goes looking for the segment files.

Thanks to an old post to the solr-dev list by Yonik, the easiest fix is to simply delete the index directory and restart your applet container (Tomcat in this case).