the culprit here: C:\Users\samsam\.m2\repository\.cache\m2e\1.4.1\26522e0d83a422eed93329ece7565cfc\min ... Here m2e is a Maven plugin that provides integration for Maven into Eclipse, and the cfs(Compound ... File format) files are Lucene index file used by m2e plugin. The plugin caches Lucene index ... and there is also a global cache in ~/.m2/repository/.cache/m2e/${m2e.version}. It's a Lucene index