Symbiote

Symbiote is a native macOS menu-bar utility that frees up your Mac's internal storage using symbolic links. Keep your apps and large files on an external drive, and they still appear right where you expect them — in /Applications, Documents, an Obsidian vault, wherever — while taking up almost no internal space.

Instead of copying or moving files by hand, Symbiote creates and maintains symbolic links (lightweight pointers) automatically, so you never have to touch Terminal.

Key features:

• Multiple source ? destination pairs, each individually toggled on or off
• Real-time syncing that only processes what actually changed (FSEvents-based)
• Auto-resumes when your external drive reconnects
• Per-pair status with live link counts and a "Sync Now" option
• Lives quietly in the menu bar
• Sandboxed and collects zero data

Symbiote is a perfect fit when your internal disk runs tight but you have an external drive sitting right there — move the bulk to the external drive and let your Mac keep working as if nothing changed.

Price: $1.99, one-time purchase on the Mac App Store. Requires macOS 15 or later.