Free file manager runs completely offline
TagSpaces is a free cross platform open source personal data manager that lets you take notes and organise files across all your devices. It runs completely offline and requires neither internet connection nor online registration. Files and notes can still be synced between devices using other cloud-based platforms. TagSpaces focuses on tagging files for sorting into searchable categories with a live preview in a side-pane. TagSpaces adds a new dimension to list views as it can incorporate tree-map or mind-map views useful for mapping projects.