Five Windows trails that can reveal who used your PC while you were away

Event Viewer, security audits, USB records and app histories can help identify recent activity on a shared Windows computer , and highlight when passwords should be changed.

If you share a Windows PC with family members, there are several ways to check whether someone has been using it without your knowledge. The most reliable starting point is Event Viewer, which records system activity with timestamps and can help establish when the machine was last active. Windows Central says Event Viewer is one of the built-in tools for reviewing application, driver, service and system records, making it a useful first stop when you are trying to reconstruct recent use. Microsoft’s own guidance also shows that Windows auditing can be configured to capture logon-related events for more detailed review.

For a fuller picture, Windows security auditing can be turned on so that sign-in and sign-out activity is logged in a way that is easier to interpret. Microsoft explains that administrators and users can enable audit policies for logon and logoff events, including workstation lock and unlock actions, remote session connections and disconnections, and other access-related events. Once this is active, Event Viewer can be checked for successful sign-ins, which are recorded under the relevant security events and can reveal which account was used and when.

USB history is another strong clue. Microsoft’s documentation on Plug and Play auditing shows that Windows can record when external devices are attached, removed, enabled or blocked, which makes it possible to identify whether a flash drive or other removable device was connected while you were away. That is especially useful if you suspect someone copied files or brought data on or off the computer. Practical guides from iTechGuides describe using Event Viewer for USB activity review, reinforcing that the operating system itself can leave a forensic trail of device use.

File and media traces can also expose recent use. VLC Media Player keeps a list of recently opened media, so if the programme is installed and someone has watched videos through it, that history may still be visible. Likewise, Windows records recent file activity in its common open-and-save dialogues, which can help reveal documents that were searched for, opened or edited. These records are not foolproof, but they can be useful when paired with system logs and device history.

Browser history should be checked as well, particularly if the computer is used for banking, shopping or other sensitive tasks. TweakTown notes that recent browsing can still provide clues even when some history has been cleared, although it may not tell the full story on its own. If you discover signs of unauthorised access, the safest response is to change important passwords immediately, especially for email, banking and social media accounts, so that any access gained through the machine is cut off as quickly as possible.