Deepnest hangs, crashes or overlaps parts? Here is why, and what to switch to.

Deepnest is still the best-known free nesting tool, and it still gets recommended in forums daily. It is also a project whose last commit was in August 2018. If it sits at zero progress for an hour, crashes when you export, or produces layouts with parts on top of each other, your machine is fine. You are running abandoned software, and there are two good ways out.

Why Deepnest hangs: the algorithm has no finish line

Deepnest nests with a genetic algorithm. It breeds generations of candidate layouts and keeps improving forever; there is no built-in stopping condition. You are supposed to watch the utilization number and press stop when it plateaus. On friendly inputs that works. On unfriendly inputs the first usable candidate never appears: issue #83 documents runs that hang at zero progress on Windows 10 with no error and no way to debug. In a LightBurn forum thread, a user gave it a full hour and had 7 of 100 parts placed before giving up. Long runs also grow the Electron app's memory use, which is how "slow" turns into "frozen". So "stuck" is partly by design (it never terminates on its own) and partly bugs that will stay unfixed.

The known failure points, with receipts

These are the issue clusters people actually hit, straight from the tracker of the original project:

• "Could not contact file conversion server." Deepnest does not parse DXF locally. Every DXF import is sent to a remote server for conversion, so no internet, or a dead server, means no DXF import at all (#76, #196).
• Crashes when exporting to DXF (#103), which is the cruelest failure: the nest finished, and then the result is gone.
• Parts overlap in the output. Issue #98 reports overlapping placements on every run for that user's files. Deepnest never re-checks its own output, so an overlapping layout looks exactly like a good one until you cut it.
• Wrong sizes after import. In #204 a 250 × 100 mm part came in at 88.2 × 35.3 mm. Forum workarounds revolve around fixing units and scale at import. Whatever tool you use: measure one known dimension after import, before you nest.

The community saw all this coming. In April 2021 someone opened issue #123, titled "Revive this project?". The original repository never merged anything again. The revival happened elsewhere.

First recommendation: switch to deepnest-next

deepnest-next is the community fork that took over, and it is free, MIT licensed and actively developed. Binaries for Windows, macOS (Apple Silicon and Intel) and Linux are at deepnest.net; v1.5.6 shipped in May 2025. Early users report that unit and millimeter conversion, a chronic sore point of the original, is handled correctly from the start. It keeps the features that made Deepnest worth using in the first place, including common-line merging and CDR import.

The honest caveats: DXF import still runs through an online conversion service, native import is listed as upcoming, and that service has had outages of its own (deepnest-next #71). The tracker also has open reports of DXF files breaking into several parts on import (#162). None of that changes the recommendation: it is free, it is maintained, and most Deepnest problems disappear when you switch. Try it before you spend money on anything, including on us.

Where NestForge takes a different approach

Three of the failure points above are not bugs you can patch, they are consequences of how the Deepnest family is built. NestForge was built around the opposite choices, so this is the honest "where it differs" rather than a feature war.

Overlaps cannot reach you silently. Every finished layout is re-checked by an independent validator that shares no geometry code with the optimizer and recomputes clearances with exact arithmetic. A layout that fails the check is discarded, not shown. The failure mode of issue #98, a nest that looks fine and cuts wrong, is the specific thing this exists to prevent.

DXF parsing is local. There is no conversion server anywhere in the pipeline. Import, nesting and export all run in your browser, which means they also run offline, and a malformed DXF produces a named error with a fix hint instead of a silent failure on someone else's machine.

Runs terminate, and results repeat. NestForge uses fixed iteration budgets: a run ends on its own, and the same parts, settings and seed produce the identical layout every time. "Let it run overnight and hope" stops being part of the workflow.

What you give up coming from Deepnest: NestForge has no common-line cutting, no CDR import and no bitmap engraving nesting, and the free tier is capped at 10 parts on 1 sheet. If shared cut lines are the reason you run Deepnest, stay on deepnest-next; that is the right tool for that job.