Record the exact stage
Note whether the failure occurred before rendering began, during progress, or while saving the output.
Copy the full error
Keep the complete message or take a screenshot. A shortened description often removes the useful part.
Describe the source
Include the game, container or file format, resolution when known, and whether the source is on an internal, external, or network drive.
Preserve the project
Do not delete the project or source while support investigates. Then use the support-request checklist.