A few CMD windows flashed at startup. Should I worry?

A quick flash by itself doesn’t tell you much. Windows updates, driver installers, and other programs can run short scripts at sign-in, so this can be harmless. Malware is possible too, but the window appearing once isn’t evidence of it.

Check Task Manager’s startup apps first. If it keeps happening, use Microsoft Sysinternals Autoruns to inspect entries that run at logon, and look at Task Scheduler for unfamiliar tasks. Don’t disable things at random; check the publisher and file path before changing anything.

On a new installation, updates and driver setup are plausible explanations. Some installers use brief command-line scripts for cleanup or setup, and several windows can appear in succession.

If it starts happening every time, or you spot an unfamiliar startup item, investigate further. Run an updated Windows Security scan, and consider a second reputable scanner if you still have a concrete reason to be concerned. A clean scan is useful, but it can’t identify what launched those windows after the fact.

If you want to find out what is launching, check startup apps and scheduled tasks while the behavior is recurring. Autoruns can show more logon entries than Task Manager. Note the entry name and executable location before deciding whether it is suspicious. A familiar vendor and expected software path are reassuring signs, though not absolute proof.