A driver that worked fine yesterday suddenly stops recognizing the phone after a routine restart, and nothing about your setup changed on purpose. This is one of the more frustrating Android USB problems because it looks like it should be your fault, but it's usually Windows Update quietly swapping a working vendor driver for a generic one it considers "better" or more current.
Windows Update includes an optional driver update channel that scans connected hardware and pushes replacements from its own driver catalog, independent of whatever you installed manually. For Android devices this catalog entry is often a generic MTP or Composite USB driver rather than the vendor-specific ADB interface driver you installed (Google USB Driver, Samsung's driver, or an OEM PC Suite driver). The generic driver handles file transfer fine but doesn't expose the ADB interface, so adb devices stops finding the phone even though it still shows up in File Explorer.
This tends to happen after a major Windows feature update, after a driver-related patch Tuesday release, or sometimes with no obvious trigger at all if the update service runs a background hardware scan.
Open Device Manager and locate the phone, usually under Portable Devices or Android Device depending on which driver is currently loaded. Right-click it, choose Properties, then the Driver tab, and check the driver date and provider. If the provider says Microsoft and the date is recent, Windows Update supplied it. Compare that against the driver you originally installed — if you used the Google USB Driver, its properties would normally show Google as the provider instead.
This restores function immediately, but on its own it doesn't stop Windows Update from repeating the swap after the next update cycle.
Windows exposes a setting that excludes driver updates from the general Windows Update flow: Settings > System > Advanced options > Additional options in newer Windows 11 builds, or via Control Panel > System > Advanced system settings > Hardware > Device Installation Settings on Windows 10. Setting device software installation to "No" (or unchecking automatic driver downloads) prevents Windows Update from silently replacing drivers for devices already installed, though it also means you'll need to update other hardware drivers manually going forward.
A more targeted alternative that doesn't touch the global setting is to hide the specific driver update using the Show or Hide Updates troubleshooter tool that Microsoft distributes for exactly this purpose, which lets you block one problematic driver update without disabling driver updates system-wide.
On Windows 10/11 Pro, Enterprise, or Education, gpedit.msc exposes a policy under Computer Configuration > Administrative Templates > Windows Components > Windows Update that can exclude driver updates from Windows Update entirely. This is more durable than the per-device setting because it survives feature updates, but it's not available on Windows Home editions.
If you previously had to disable driver signature enforcement to install an unsigned OEM driver, a Windows feature update can silently re-enable enforcement and knock the unsigned driver back to a non-functional state. If the driver disappears entirely rather than being replaced with a generic one, check signature enforcement status again rather than assuming Windows Update pushed a different driver.
Once the correct driver is back and confirmed with adb devices returning a serial number and device status, the fix should hold until the next major Windows feature update, at which point it's worth repeating the Device Manager check once rather than assuming it's permanent.