This page describes how to troubleshoot the RendererNoRenderFinishedEventReceivedError error in Looker. This error message usually indicates an issue with the Chromium renderer that generates PNG and PDF visualizations for downloads and schedules.
Troubleshooting Chromium renderer compatibility
Use the following decision tree to troubleshoot renderer compatibility issues. Open the decision tree in a new tab to zoom in.
Troubleshooting steps
The following sections describe the scenarios in the tree in further detail.
Step 1: Verify Chromium version
The root cause of RendererNoRenderFinishedEventReceivedError could be a mismatch between the Looker instance and the version of Chromium or Google Chrome that's installed on the customer's host server.
To pinpoint the exact Chromium version and its installation path, use the following commands:
chromium --version
which chromium
Compare the output version against the list of Looker-compatible versions. Refer to the Customer-hosted installation of rendering software page to see the list of supported versions.
If the version is not compatible, move to Step 2B: Perform Strategic Rollback. Otherwise, move on to Step 2A: Review installation and configuration
Step 2A: Review installation and configuration
If you're using a customer-hosted Looker instance, review the rendering software installation documentation to ensure correct configuration.
If everything looks correct, move on to Step 3A: Analyze logs.
Step 3A: Analyze logs
Scrutinize Looker logs for any errors related to Chromium's state, its connection to the devtools, or any failed communication attempts. Look for recurring patterns or specific error messages that can provide clues to the underlying issue.
If you can't find any issues in the logs, move on to Final review and support.
Step 2B: Perform strategic rollback
If the Chromium version is incompatible, a strategic rollback to a known compatible version (for example, Chromium 97, 109, or 114) is often the most effective solution. Contact Looker Support if you need help rolling back your Chromium version.
During the rollback process, you might encounter the following issues.
Step 3B: 404 errors and missing packages
Encountering 404 errors or missing packages can disrupt the rollback procedure. Ensure that the necessary package repositories are correctly configured and accessible. If needed, manually download and install missing packages.
Step 3C: Permission issues
Insufficient permissions can hinder the creation or modification of directories required for the rollback. Grant the appropriate user permissions to execute the rollback process. Use sudo or equivalent commands to elevate privileges temporarily if necessary.
Step 3D: dpkg frontend lock errors
In Debian-based systems, the dpkg frontend lock can prevent concurrent package operations. Wait for any ongoing package operations to finish. If there appears to be a frontend lock that doesn't go away with time, take a backup of your instance and use the command to force unlock the frontend:
sudo rm /var/lib/dpkg/lock
Step 3E: Disable Chromium auto-updates
In customer-hosted environments, automatic Chromium updates can inadvertently introduce compatibility issues. Implement measures to prevent Chromium from auto-updating. Establish a routine to proactively monitor the Chromium version, and perform manual updates only when compatibility with Looker is ensured.
Final review and support
If these troubleshooting steps fail to resolve the error, contact Support to troubleshoot further.