USB or MTP device is not recognized or shows Code 43: test a data-capable cable

A phone, media player, camera, or other USB device may charge when connected to a Windows 10/11 computer but never establish a usable data connection. File Explorer may not show it, its MTP storage may be unavailable, or Device Manager may show an unknown USB device with Code 43. A charge-only, internally broken, out-of-spec, or poorly seated cable can carry power while its data conductors do not provide a stable USB connection.

This writeup tests the cable before changing Windows drivers. It does not assert that every Code 43 is a cable fault. Code 43 means that Windows stopped a device after a driver reported a problem; the cable becomes the likely cause only when a controlled cable/port/device comparison isolates it.

Searchable Windows error codes and exact messages

Do not add Code 10, Code 31, or another Device Manager code unless that exact code is visible. Those codes route to driver-start or device-add diagnostics and are not interchangeable with Code 43.

Use this procedure when:

• the device receives power or reacts when connected, but Windows cannot use its data connection;
• Windows displays Code 43, a descriptor-request failure, USB device not recognized, or no MTP/File Explorer device;
• the connector type permits a replacement cable;
• the device is unlocked and, when applicable, has File transfer, MTP, USB storage, or the manufacturer-required data mode selected;
• the same Windows USB port can operate a known-good data device, or another port produces the same result with the suspect cable; and
• a known data-capable replacement cable is available for an A/B comparison.

The strongest match is a device that fails with Cable A and works repeatedly with Cable B on the same known-good port without a driver or Windows change.

Do not use the cable conclusion when all USB devices fail on the same computer, the connector is physically damaged or contaminated, the device is not receiving stable power, the device remains locked, or its USB mode is deliberately set to charging only.

It also does not apply when:

• a fixed captive cable cannot be substituted;
• the problem concerns USB-C video, docking, charging wattage, Thunderbolt authorization, or alternate-mode capability rather than ordinary USB data;
• Windows recognizes the storage device but reports a file-system, permissions, capacity, or I/O error;
• the device fails with multiple proven cables on multiple known-good computers;
• the cable or connector becomes hot, sparks, smells burnt, has exposed conductors, or fits loosely enough to interrupt power; or
• a corporate USB-control policy, endpoint-security product, or Device Installation Restriction blocks the device.

Stop using visibly damaged hardware. This procedure is not permission to keep manipulating a broken port.

The cable's advertised USB revision, internal wire break location, manufacturer, age, and the exact moment it failed may remain unknown. The exact Windows build may also remain unknown because the primary test is physical and comparative.

The following may not remain unknown before declaring the cable responsible:

• which physical device, cable, and computer port were tested;
• whether the portable device was unlocked and placed in data-transfer mode;
• the complete Device Manager status, including any visible code;
• whether the port can enumerate another known-good data device;
• whether the replacement cable is independently known to carry data; and
• whether the original failure returns when only the suspect cable is reintroduced.

• A known data-capable replacement cable with the correct connectors
• At least one known-good USB data port, preferably a direct motherboard/laptop port rather than an unpowered hub
• Access to Device Manager
• The portable device's screen, unlock method, and USB-mode control when applicable
• A small, non-sensitive test file for transfer verification
• A safe-eject method for devices that expose removable or portable storage
• A written test matrix identifying the cable, port, device, and result of each connection

Do not use a cable merely because it charges another device. Charging proves power conductors, not a working data path.

1. Save work on the Windows computer and on the portable device.

2. If the device currently appears in File Explorer or a media application, use Eject or the application's disconnect command before unplugging it.

3. Disconnect unrelated USB storage, docks, and hubs so Device Manager changes can be attributed to the test device.

4. Inspect the suspect cable and both connectors. Stop if there are exposed wires, bent contacts, corrosion, debris that cannot be safely removed, heat damage, or an unstable connector shell.

5. Connect the test device directly to the chosen computer port. Do not use a hub, extension, front-panel adapter, or dock during the baseline test.

6. Unlock a phone, tablet, camera, or media player. Select its data mode when prompted. Common labels include File transfer, MTP, Transferring files, or USB storage. Do not assume that charging mode exposes files.

7. Open Device Manager:

   devmgmt.msc
   

8. Select View > Devices by connection and also note entries under Portable Devices, Universal Serial Bus controllers, and Other devices. Record the exact device name, status, and event time before changing the cable.

1. Establish the failure with the suspect cable. Reconnect it once, wait at least 30 seconds, and record:

   • whether Windows plays a connection/disconnection sound;
   • whether the device charges;
   • whether the device offers a USB-mode prompt;
   • whether File Explorer or the manufacturer's application sees it; and
   • the exact Device Manager entry and status.

2. If Device Manager shows an unknown or warning-marked device, open Properties > General and copy the complete Device status. For Code 43, also open Events and record the newest Device configured, Device started, Device not started, or migration event. Do not interpret the event text beyond what it states.

3. Prove that the selected port carries data. Safely disconnect the test device, then connect a simple known-good USB data device to the same port. Confirm that Windows identifies it and can complete a small read operation. If the known-good device also fails, stop: the port, controller, power path, or Windows USB stack remains suspect.

4. Reconnect the original device with the suspect cable to a second known-good direct USB port, when available. If it works consistently on the second port, the first port or its path—not the cable alone—is implicated.

5. Keep the original device and known-good port unchanged. Replace only the cable with the verified data-capable cable.

6. Unlock the portable device and select the same data mode. Wait for enumeration. Record whether:

   • Windows identifies the device by its real name;
   • the Code 43/unknown-device entry disappears;
   • a Portable Devices or storage entry appears; and
   • files become accessible.

7. Transfer one small, non-sensitive test file from the computer to the device when supported. Open it from the device or copy it back to a different local filename and compare the file size. Do not use the only copy of an important file as the test.

8. Safely eject, disconnect, and reconnect with the replacement cable two additional times. Require three successful enumerations in total.

9. For a controlled confirmation, safely disconnect and reintroduce the suspect cable once on the same port. If the failure returns and replacing only the cable restores operation again, the cable diagnosis reaches this article's evidence threshold.

10. Stop without declaring a cable fix if both cables fail, results vary by port, moving either connector changes the result, or the device fails on another computer. Those outcomes require port, connector, device, power, or driver diagnosis.

Branch A — The replacement cable passes the controlled comparison

1. Retire or clearly label the suspect cable as charge-only or defective. Do not return it to a general cable bin where it can recreate the problem.

2. Use the verified cable directly between the Windows computer and device.

3. Unlock the device and select its data-transfer mode.

4. Wait for Windows to finish identifying the device. If File Explorer does not refresh, select Action > Scan for hardware changes in Device Manager once. Do not uninstall USB host controllers.

5. If an old Unknown USB Device entry remains only while hidden devices are displayed, leave it alone unless it creates an active conflict. A historical non-present entry is not a present failure.

6. Complete the test transfer and safely eject the device.

Branch B — The replacement cable works only after selecting MTP/File transfer

1. Keep the replacement cable; it has proved a data path.

2. On each connection, unlock the device and select File transfer/MTP rather than Charge only.

3. If the device offers a trusted-computer prompt, approve only a computer you control. Do not permanently trust a public or unknown computer.

4. If the device allows a default USB configuration, change it only when the security tradeoff is accepted. Requiring unlock and a per-connection choice is safer for many portable devices.

Branch C — Both cables fail but the same device works on another computer

1. Do not discard either cable based on this test.

2. Test a different direct port on the affected Windows computer.

3. Record the USB controller and device status in Device Manager.

4. Obtain the computer manufacturer's exact-model chipset/USB driver and firmware guidance. Do not install a generic driver selected only by a similar product name.

5. Route the case to a USB controller, port, device-installation-policy, or driver-specific writeup.

Branch D — The device fails with proven cables on multiple computers

1. Stop Windows-side repair.

2. Inspect the device connector and its USB mode.

3. Use the device manufacturer's recovery or hardware-service procedure. A repeated cross-computer failure points away from the Windows installation.

• The device works with the replacement cable on repeated reconnects: keep the replacement cable in service and retire the suspect cable.
• The device works only when unlocked and set to File transfer/MTP: the cable is functional; the remaining behavior is the device's connection-mode/security setting.
• Every device fails in one port but works in another: diagnose the failed port or its internal/hub path.
• One device fails everywhere with multiple proven cables: diagnose the device connector, device firmware, or device hardware.
• Code 43 remains with the replacement cable but disappears on another computer: diagnose the affected computer's USB controller/driver path.
• The entry alternates rapidly between connected and disconnected when the connector moves: stop using the connector; physical damage or poor fit is likely.

• Do not treat charging as proof that a cable supports data.
• Do not conclude that every Code 43 is a cable problem.
• Do not uninstall every USB controller, delete the USB device class, or use a registry cleaner before the physical comparison.
• Do not repeatedly reconnect a hot, damaged, corroded, or loose cable or port.
• Do not format a storage device that Windows cannot enumerate.
• Do not enable USB debugging merely to make ordinary MTP file transfer work.
• Do not approve a trust prompt on a computer you do not control.
• Do not test with the only copy of an important file.
• Do not claim the procedure repaired Windows; the successful branch replaces a failed or unsuitable physical data path.

The primary resolution makes no persistent Windows configuration change.

1. If the replacement cable introduces a new problem, safely eject and disconnect the device.

2. Restore the portable device's prior USB-mode preference if it was changed.

3. Reconnect the original cable only if it is physically safe and only long enough to confirm the recorded baseline. A confirmed defective cable should remain retired.

4. If Scan for hardware changes was used, no rollback is required; it only asks Windows to enumerate present hardware.

5. If any driver, USB controller, registry value, or device policy was changed outside this article, document and reverse that separate change using its own backup. Do not represent that external change as part of this rollback.

1. Connect the device with the replacement cable to the proven port three separate times.

2. On each connection, require Windows to identify the real device rather than Unknown USB Device.

3. Confirm that Device Manager shows This device is working properly or no active warning for the device.

4. Transfer a small test file in the required direction, open or copy it back, and compare its size to the original.

5. Safely eject the device and confirm that a later reconnection remains successful after a Windows restart.

6. Record the replacement cable, port, device mode, Windows version, and final Device Manager state. Do not record the repair as verified if success occurred only once.

Confidence is approximately 80% that the cable/data path is the operative cause only when the same device and same known-good port fail with the suspect cable, work at least three times with a verified data-capable cable, and fail again when only the suspect cable is reintroduced. Two source cases reported that replacement with a data-capable cable restored file transfer or repeated recognition; TechXplored has not independently reproduced those cases.

Confidence is lower when the replacement cable was not independently proven, the port changed at the same time, the device mode changed without being recorded, or the result was a single successful connection.

Stop immediately for heat, sparks, exposed conductors, liquid/corrosion, physical connector damage, unstable power, failure across multiple computers, or any prompt to format an unrecognized storage device. Stop the cable procedure and escalate to driver, controller, policy, or hardware diagnosis when the controlled comparison does not isolate the cable.