FAQ and Troubleshooting

FAQ & Troubleshooting

General

Is it free / open source? Yes — AutomataLab is released under the MIT License.

Do I have to install it? No. There's a web build with the same engine. The desktop app adds native file dialogs and auto‑updates.

Where are my files stored? Wherever you save them — machines are plain .autolab.json files (see File Format). Nothing is uploaded anywhere.

Editing

The canvas seems frozen — I can't add or delete states. This was a bug fixed in an older release. Editing is intentionally locked only while a simulation is actively running. If a run has finished (Accepted / Rejected / Stuck), the diagram is fully editable again; your first edit clears the result and returns to Idle. If you're on an older build, press R (Reset) first, or update to the latest version (v4.1.0+).

Delete doesn't remove a state. Make sure the element is selected (click it first) and that a run isn't in progress. You can also right‑click → Delete.

My transition won't connect. Hover the source state until the connection dot appears, then drag to the target — or use the Add transition tool in the left rail.

Simulation

My DFA "rejects" instead of erroring on a missing move. That's correct behaviour: a partial DFA rejects when it has nowhere to go. AutomataLab flags the missing transition as a warning and offers a one‑click Complete DFA fix. See Validation & Alphabets.

My run says stuck. The TM/LBA loop guard halted it after the step limit (default 10000). If the machine genuinely needs more steps, raise the limit in the toolbar; if it's looping, fix the transitions.

My LBA rejects unexpectedly. An LBA's head is bounded to the input region [0, n]; a move past either end halts and rejects. Keep the head within the marked ⊢ … ⊣ region. See Turing Machines & LBA.

The NFA computation view "merges" branches — is that a bug? No. For NFA/ε‑NFA the view is a trellis: paths reaching the same state at the same step are merged (with a ⇉ₙ chip), because finite automata compute over a set of states. NPDA keeps a real branching tree. See Simulation.

Updates & installation

Auto‑update isn't working. Over‑the‑air updates work from v1.0.2 onward. Builds v1.0.0/v1.0.1 lack the updater capability and must be updated manually once.

The OS warns about an unidentified developer. Allow the app via System Settings → Privacy & Security (macOS) or More info → Run anyway (Windows SmartScreen).

Still stuck?

Open an issue on the tracker with your machine file and the steps to reproduce.