Troubleshooting

Symptom	Fix
First start is very slow, or the client gives up	it is downloading the dependencies; run uvx --from b123d-print b123d-print-mcp --help once in a terminal, then restart the client
Bambu Studio says "The 3mf file has invalid config, load geometry data only"	expected: the file has no Bambu project settings, only the shape. Click OK; the part loads and you slice it with your own settings (Arrange with A if it lands off the plate)
Client says uvx not found	use the full path from which uvx (Windows: where.exe uvx) as the command
Model never looks at the renders	your client doesn't pass tool images to the model; open out/*.png yourself
timed out after 120 s	a slow or endless script; raise --timeout if the part is genuinely heavy
[FAIL] timeout ... time limit reached while running ...	check ran out of time; the findings above it are complete. Raise --check-timeout (B123D_PRINT_CHECK_TIMEOUT), or narrow the check it names (time limit)
blocked in part scripts: ...	the script tried the network, a subprocess or files outside the workspace; part scripts only need build123d
unknown setting(s)	a typo in config.toml or b123d-print.toml; the message lists the known keys (Settings)
HTTP server exits right after starting	it prints why: a missing or short token, an unreadable token file, a workspace it cannot write; see Over the network
Holes print small	calibrate hole_comp with the coupon
Windows: sandbox says "no OS sandbox here"	expected: Windows has none (Sandbox); run the server in WSL2 with bubblewrap, or in Docker, for untrusted scripts
Windows: install fails with a path-too-long error	the deepest file in the uv cache is about 165 characters below the cache folder; turn on long paths, or point UV_CACHE_DIR at a short folder such as C:\uv
Linux: sandbox says "audit hook only"	install bubblewrap (apt install bubblewrap); on Ubuntu 24.04 unprivileged user namespaces must also be allowed (sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0) — or use Docker

Still stuck? Open an issue with the output of b123d-print --version, b123d-print config and the error.