Preferences and hotkeys

In Edit ▸ Preferences ▸ Add-ons ▸ Layer Comp:

• Turn the hotkeys off, or rebind them.
• The file type for Export Layers.

Hotkeys only take a key while their tool can run, and never in UV mode. On a Mac, Cmd stands in for Ctrl: Cmd+A, Cmd+D, Cmd+J, Cmd+T.