What is the purpose of the lost+found folder in Linux and Unix? (2014)
Summary
This Unix & Linux Stack Exchange post explains the purpose of the lost+found directory created by ext2/3/4 filesystems. It describes how fsck uses lost+found to store recovered, previously unlinked data after a crash or filesystem corruption, and notes that the directory is typically per-filesystem and normally empty unless corruption or recovery occurred. The discussion includes nuances about permissions, potential nuisance when searching, and historical context from multiple community answers.