Match the tool to the symptom
Missing textures, a launch error after an interrupted update or a suspected damaged installation are reasons to consider the launcher's file-verification tool. The tool compares installed data with what the launcher expects and can reacquire files that need replacing. It is a narrower operation than reinstalling the operating system, and often a sensible early check for one affected game.
It will not repair an unstable network connection, a blocked cooling vent or an unsupported graphics card. If every game fails in the same way, keep the wider system in the investigation. If one title developed trouble immediately after a patch, record that timing rather than assuming all local files are corrupt.
Prepare before starting
Exit the game and preserve saves or custom modifications according to the developer's instructions. Verification can restore original game files that a mod deliberately changed. Keep a record of the mod setup so you can rebuild it if necessary, but test the unmodified game first when troubleshooting.
In Steam, open the game's Properties, select Installed Files and choose the integrity-verification option. Let it complete without running another intensive disk task. Steam notes that some local configuration files may not verify and do not necessarily indicate a broken installation. Read the resulting message instead of treating any nonzero count as proof of hardware failure.
Repeat the original test
After any replacement download finishes, launch the same game and reproduce the situation that failed. A successful start does not establish that a crash occurring halfway through a level has been fixed. Keep the comparison specific.
If the fault remains, note what verification changed and move to the developer's relevant troubleshooting guidance. Repeating the same verification several times without a changed result adds little evidence. Supply support with the error text, game version, whether mods were present and whether files were reacquired. That creates a more useful report than a general claim that every possible fix has been tried.
