Lighthouse error: NO_SCREENSHOTS / SPEEDINDEX_OF_ZERO

What’s actually happening

Performance run aborts with NO_SCREENSHOTS, or completes with a Speed Index of 0 and a score that cratered. Speed Index is built from the filmstrip — Chrome samples paint frames and measures how fast pixels fill in. No usable frames means no Speed Index, and Lighthouse can't score the run. Pages that paint nothing, paint-then-blank, or animate for the whole load are the typical triggers; M118 made this far more common.

Common causes

• Nothing visible ever paints — blank page, content rendered entirely off-viewport, or render blocked behind a never-firing event.
• Content paints and then disappears (splash screen removed, element hidden) so frames don't represent stable content.
• A full-screen video or animation runs for the entire load and Chrome exhausts its 450-frame filmstrip limit (page taking >10s with constant motion).
• Chrome M118 regression: a tracing/screenshot change caused widespread NO_SCREENSHOTS even on pages that scored fine on M117.
• Headless/sandbox capture failure in CI — Chrome can't grab frames due to GPU or shared-memory limits.

How to fix it

1. Update or pin Chrome to dodge the M118 regressionThis spiked with Chromium M118 (Lighthouse issues #15460/#15556). Move to a newer Chrome where it's fixed, or temporarily pin to M117 in CI. Confirm your runner's Chrome version with `chrome --version` before blaming the page.
2. Make sure something paints and stays paintedIf you have a splash/loader that's removed on load, ensure real content is visible within the trace and doesn't blank out. Render-then-hide patterns produce empty or unusable filmstrips.
3. Kill the all-load animation or video autoplay for the auditA hero video or full-screen animation that never stops keeps Chrome capturing frames until it hits the 450-frame cap on slow pages. Pause autoplay, shorten the loop, or speed up load so motion isn't constant past 10s.
4. Fix headless capture in CIAdd `--chrome-flags="--disable-dev-shm-usage --no-sandbox"` (sandbox only where safe) and give the container more shared memory. GPU/shm starvation makes Chrome collect zero screenshots regardless of the page.
5. Rule out an offscreen-only renderConfirm content actually lands in the viewport. If everything is positioned offscreen or the viewport is mis-sized, Chrome films a blank frame and Speed Index comes back 0.