Quick check: Run the related device test and keep it open while trying these steps.
Confirm the simple case
Put the headset on according to its L and R markings. On our speaker test, reduce volume and play Left, then Right. Note which ear actually receives each tone. Center should be heard in both. If the left tone arrives in the right ear, first check whether the headphones are worn backward.
Inspect the signal path
Disconnect and reconnect a wired headset; a partly inserted plug can produce strange stereo results. Verify that an adapter, audio interface or receiver has its channels connected correctly. Try the same headphones on another device. If the reversal follows the headphones, look at the cable or headset; if it remains with the PC, inspect the PC output route.
Check processing and balance
Surround virtualization, channel-swapping software and audio-interface mixers may deliberately change routing. Temporarily disable such effects for a baseline test. Mono audio combines channels, so it can make Left and Right sound similar; check Windows accessibility audio settings if the tones are not isolated. Restore any feature you use after the comparison.
When only games sound reversed
If this basic test is correct but one game places footsteps on the wrong side, examine that game’s audio mode and virtual surround setting. A test tone verifies basic stereo assignment, not whether a particular game has configured positional audio correctly. Avoid changing the entire system until you know the problem occurs outside that one application.
After each change, test the device again. Change one setting at a time so you can identify what helped.
Further reference: Official device or browser documentation ↗