Why Did a Chromium Window Open After Startup When I Don’t Have Chrome Installed?

Run a full malware scan, preferably including rootkit detection. You can use Windows Security for an offline or full scan, and a reputable second-opinion scanner if needed. Also keep an eye on Task Manager and investigate any unfamiliar processes by searching their exact names. Don’t download random ‘cleaner’ tools or allow unknown programs through security prompts.

Chromium and Google Chrome aren’t the same thing. Many legitimate apps use Chromium components to display web content, so seeing a Chromium-based window doesn’t automatically mean Chrome—or malware—is installed. Check your installed programs and startup apps for anything unfamiliar, then run a complete security scan.

A screenshot or the exact window title would make this much easier to identify. If it happens again, avoid clicking links or entering information, take a photo or screenshot, and note which programs launch at startup. You can also search for Chromium-based applications in the installed-programs list rather than assuming the browser itself was installed.

Windows Defender includes a command-line scanner that can perform a deeper scan. From an elevated PowerShell or Command Prompt, you can run: "C:Program FilesWindows DefenderMpCmdRun.exe" -Scan -ScanType 2. Afterward, review Startup apps and recently installed software. If the window never returns and the scans are clean, it may have been a one-time launch from a legitimate app or update.