This section provides solutions for some common problems. Symptom: Nix operations (in particular the nix-store operations --gc, --verify, and --clear-substitutes — the latter being called by nix-channel --update) failing: $ nix-store --verify error: Db::del: Cannot allocate memory Possible solution: make sure that no Nix processes are running, then do: $ cd /nix/var/nix/db $ rm __db.00*