Wi-Fi adapter Code 43 or Code 45: the device stopped or is not present

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Code 43 is CM_PROB_FAILED_POST_START: a driver told Windows the device had failed, and Windows stopped it. Code 45 is CM_PROB_PHANTOM, which simply means the device this entry describes is not attached. Microsoft’s documented remedy for Code 43 is to uninstall and reinstall the device, and for Code 45 to reconnect the hardware – so start there rather than with registry surgery.

netsh wlan show drivers
Get-PnpDevice -Class Net | Format-Table Status,Problem,FriendlyName
Get-NetAdapter -Name "Wi-Fi"

1. Rule out the switches first: the physical wireless switch or function key, and aeroplane mode in Settings under Network and internet.
2. In Device Manager, uninstall the wireless adapter, tick the option to remove the driver software if offered, and reboot so Windows reinstalls it.
3. Replace whatever Windows installs with the driver for your exact model from the laptop maker’s support page, not the chipset vendor’s generic package.
4. For a USB adapter, open its properties, Power Management tab, and clear the option that lets the computer turn the device off.
5. For a Code 45 entry, choose View then Show hidden devices in Device Manager and remove greyed-out wireless adapters for hardware that is no longer in the machine.

Apply the machine’s current UEFI firmware as well. On many laptops the wireless module’s own firmware ships inside it, and a firmware fault produces a Code 43 that no driver reinstall will clear.

If the adapter reports working properly and survives a sleep, stop here. If it does not, the next section explains what each code is actually asserting.

Why it happens

Code 43 is not Windows diagnosing hardware. Microsoft’s description is that one of the drivers controlling the device told the operating system the device had failed, in response to a device-state query, and that the stack then reported the device as failed. Windows halted it on the strength of that report. This is why so many Code 43 faults clear with a driver reinstall or a firmware update: the silicon was fine and the driver reached a state it could not recover from. A wireless card that fails to load its firmware blob at start-up produces exactly this.

Code 45 makes a much narrower claim: the hardware device described by this entry is not currently connected to the computer. For a USB dongle that has been unplugged, that is simply true, and the entry is a ghost that only appears when hidden devices are shown. Microsoft’s own resolution for Code 45 is that no action is needed and the error clears when the device is reconnected. For an internal module it means the card is no longer being seen on the bus at all, which is a seating, firmware or hardware question rather than a driver one.

The other two codes describe different failures again. Code 12 is CM_PROB_NORMAL_CONFLICT: the device cannot find enough free resources it can use. Code 28 is CM_PROB_FAILED_INSTALL, no driver installed at all – the normal state of a laptop’s wireless adapter immediately after a clean Windows installation, and the reason a fresh install on a machine with no wired port is such an awkward place to be.

Full reference

What each code asserts

Checking what is actually loaded

netsh wlan show drivers is the most useful single command here, because it prints the driver name, provider, version and date alongside the radio types and security features the adapter reports supporting. Compare that output against the package you believe you installed. A driver that says the provider is Microsoft when you installed a vendor package tells you the install did not take, or that Windows replaced it afterwards.

Order of work that saves time

1. Confirm the radio is not simply switched off in software or hardware.
2. Read the problem code rather than the icon. Code 43, 45, 12 and 28 look identical in the device list and need four different responses.
3. Uninstall with the remove-driver option and reboot. This is the documented resolution for Code 43, and it costs one restart. For Code 28 the documented resolution is different: go to the hardware manufacturer’s site for the current driver, because there is no driver installed to reinstall.
4. Install the vendor’s model-specific driver, then update the machine’s UEFI firmware.
5. Only then start moving hardware. Reseating a module is disruptive and rarely the answer on a machine that was working yesterday.

Persistent Code 43 after a clean driver install

This is the point at which the hardware signal becomes strong. The code means a driver reported a device failure, and a clean, model-specific driver reporting the same failure on a machine with current firmware is telling you something. Test with a USB adapter first: if wireless works perfectly through a dongle, the rest of the machine and the Windows installation are healthy, and the internal module is the remaining variable. On most laptops that module is an inexpensive, replaceable part.

Unsupported Windows builds and drivers

There is one version of this that no amount of driver work reaches. When a machine is running a Windows release the hardware vendor has stopped publishing drivers for, the driver you need may only exist for a current release. That is a genuine dead end rather than a difficult fix, and the honest answer is to move the machine to a Windows version the vendor still supports – or, where the hardware itself cannot run one, to fit a USB adapter or replace the machine.

Every code this article covers

Confirm the fix worked

1. Device Manager reports the adapter as working properly, with no warning marker and no problem code.
2. netsh wlan show drivers shows the driver name, provider, version and date you meant to install.
3. Connect to a network and confirm an address and DNS servers on the wireless adapter with ipconfig /all.
4. Sleep the machine, resume it, and confirm wireless reconnects on its own without being disabled and re-enabled.
5. Reboot and confirm the driver version has not been replaced by a Windows Update package overnight.

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