Code 45 is a Device Manager status. Microsoft defines it as:
“Currently, this hardware device is not connected to the computer. (Code 45)” [R1]
In Microsoft's driver documentation, Code 45 is named CM_PROB_PHANTOM and means that the device is not present. [R1]
This is important because Code 45 is not the same as a missing driver or a device that has reported a failure.
It usually means Windows remembers the device, but cannot currently see it.
Start by asking whether the device should be connected
If this is a removable device — such as a USB drive, headset, mouse, keyboard, camera, dock, or other peripheral — check whether it is physically connected.
Microsoft's recommended resolution for Code 45 is simply to reconnect the hardware. [R1][R2]
When the device is reconnected successfully, Microsoft says the Code 45 status should disappear automatically. [R2]
For USB devices, check the physical path
If the device is plugged in but Windows still does not see it, check the connection before changing drivers.
For USB peripherals, Microsoft recommends:
- unplugging the device and reconnecting it;
- trying another USB port;
- checking whether a USB hub has power;
- bypassing the hub and connecting directly to the PC;
- checking the cable for damage;
- checking the battery or power source where applicable. [R3]
These tests help separate a Windows configuration problem from a failed cable, port, hub, or unpowered device.
Why can a disconnected device still appear in Device Manager?
Windows can keep information about hardware that was previously connected.
Microsoft calls these non-present devices or phantom devices. They are devices that were physically removed but whose device records still exist in Windows. [R4]
Device Manager normally hides some non-present devices. If hidden devices are shown, an old device entry can therefore appear even though the hardware is no longer attached. [R4]
In that situation, Code 45 is describing the device's state rather than reporting a new fault.
Do I need to reinstall the driver?
Not merely because Code 45 exists.
Code 28 specifically means that drivers are not installed. Code 43 means that a driver reported a device failure. Code 45 means the device is not currently present. [R2]
Those are different findings.
If reconnecting the device makes it reappear normally, there is no reason to reinstall its driver just to clear Code 45.
If the device is physically connected but Windows still cannot detect it, then the next investigation depends on the device type. Connection, power, port compatibility, driver state, and the device itself may all need to be checked.
What if the device is built into the PC?
For an internal device that should always be present, Code 45 is more significant.
The code still only tells us that Windows currently regards the device as absent. It does not tell us why.
Restart the PC and check Device Manager again. If the device remains absent, use the PC manufacturer's diagnostics and support information for that hardware. A built-in device disappearing can require device-specific driver, firmware, or hardware investigation.
Do not assume that reinstalling every system driver will make a missing device return.
Should I remove old Code 45 entries?
Usually, no action is required for an old device that you intentionally disconnected.
Microsoft's driver documentation says users normally should not need to interact with non-present devices. [R4]
If an old hidden entry belongs to hardware you no longer use, it is not the same problem as a currently connected device failing to work.
How do I know it is fixed?
Do not stop when Device Manager refreshes.
Reconnect the intended hardware and confirm that:
- Windows detects the device;
- Code 45 is gone;
- the device can perform its normal function.
For example, confirm that a USB drive can be opened, a headset can play or record audio, or a camera can capture an image.
The problem is resolved when the device is present and usable again, not merely when its old Device Manager entry changes.