Solved: Chromecast “Source not Supported” Error When Attempting to Cast

Problem

Despite it previously working, I see a Source not Supported error when attempting to Chromecast to a device. This also occasionally manifests itself as a device not showing up for Chromecasting.

Solution

The solution in my case was to set the Load Media Router Component Extension setting to Enabled.

• Open Chrome
• Navigate to chrome://flags/#media-router
• Search for Router Component or similar
• Set from Default to Enabled

In my case, some organization-managed settings had changed defaults away from what they were previously.

Happy casting!