Web App Loading Issues#

Use this page when your export folder exists but Cellucid won’t load it (or loads it incorrectly).

Note

The web app has a comprehensive troubleshooting page for loading here: Troubleshooting (data loading). This page is the R-export-focused shortcut.

Symptom: “I can’t select a folder / the picker doesn’t show folders”#

Likely causes

  • You denied directory access.

  • An embedded or managed-browser policy blocked directory selection.

  • You are on mobile; Cellucid’s supported loading workflows are desktop workflows.

Fix

  • Open the standalone app in a supported current desktop browser and click Prepared.

  • If organizational policy forbids directory selection, choose server mode: Server Mode (CLI + Python)

Symptom: “Dataset loads forever / spinner never stops”#

Likely causes

  • Extremely large exports (many genes/files)

  • Browser struggling to scan the directory tree

Fixes

  • Export fewer genes (gene panel).

  • Use quantization and compression.

  • Consider server mode for large datasets.

Symptom: “Canvas is blank / WebGL context lost”#

Likely causes

  • GPU/WebGL issues

  • Dataset too large for GPU memory

Fix

  • Confirm hardware acceleration and WebGL2 are enabled, then update the browser, operating system, and GPU driver when applicable.

  • Reduce dataset size (subset cells, reduce layers).

  • See system requirements: System requirements

Symptom: “CORS blocked” when loading from a hosted URL#

Likely cause

  • You hosted the files on a server that does not send the required CORS headers.

Fix

  • Use the supported GitHub exports workflow (Host Exports for Sharing).

  • Or use server mode (Python) which handles headers appropriately.

Symptom: “It loads but labels/fields are wrong”#

Likely cause

  • Row order mismatch in the export inputs.

Fix

Next steps#