USB scanner detected but scan software cannot see device

Scenario

Windows detects the scanner, but the vendor scan application claims no device is connected.

Recommended Resolution Path

1. Check whether the scanner driver exposes TWAIN, WIA, or the vendor service expected by the app.
2. Verify the device is not connected through an unstable hub or dock.
3. Test with the native Windows scan function to separate hardware from application issues.
4. If the scanner works elsewhere, compare runtime dependencies and local permissions on the failing PC.

Technician Notes

Document what changed, what confirmed the fix, and whether the issue points to a broader standards gap worth addressing for the client.