Knowledgebase
: On the Android device, change USB mode to “File Transfer / MTP” before connecting. Also, in Device Manager, uninstall the generic USB hub driver and let it reinstall. 7.3 High CPU Usage by System process when connecting MTP device Cause : Buggy MTP device or corrupted file on device causing infinite retry loops in wpdbusenum.sys ’s enumeration logic. Less common on Windows 10 than on 7.
bu wpdbusenum!WpdBus_EvtDevicePrepareHardware The wpdbusenum.sys driver is a masterpiece of elegant design – only a few dozen kilobytes in size, yet it orchestrates the entire portable device ecosystem on Windows 10. Without it, your phone’s photos, your camera’s videos, and your MP3 player’s music would remain inaccessible without a drive letter and a full file system lock.
Also relevant:
logman start wpdbusenum -p 6faff1f0-1c5e-4b5b-9d71-3fdcf5d664e7 -o wpdbus.etl -ets Decode with tracefmt.exe from WDK. Enable driver verbose logging via:
1. Introduction: A Driver You’ve Never Heard Of If you’ve ever plugged an Android phone, an iPhone (via iTunes), a digital camera, or a portable media player into a Windows 10 PC and watched files appear almost magically in File Explorer, you’ve directly benefited from a quiet, low-level system component: wpdbusenum.sys – the Windows Portable Device Bus Enumerator Driver . wpdbusenum fs driver windows 10
HKLM\SYSTEM\CurrentControlSet\Enum\SWD\WPDBUSENUM Each enumerated portable device gets a subkey. This is where Windows caches device metadata, capabilities, and friendly names. Deleting entries here (as part of troubleshooting) forces re-enumeration on next connection.
Understanding its role demystifies why some devices show up as “Portable Device” while others as “USB Drive”. For IT professionals, developers, and power users, knowing how to troubleshoot wpdbusenum.sys issues is a valuable skill. : On the Android device, change USB mode
| Feature | MTP (via wpdbusenum.sys ) | USB Mass Storage | |---------|----------------------------|------------------| | Driver involved | wpdbusenum.sys → WUDFRd → WpdMtpDr | USBSTOR.SYS → PARTMGR.SYS → DISK.SYS | | Drive letter | No (appears under “This PC” as a portable device) | Yes | | File system access | Mediated by MTP commands | Direct block-level access | | Safely remove required? | Not usually (transactions are atomic) | Yes | | Supports simultaneous PC + device access | Yes (device can modify while connected) | No (risk of corruption) |
HKLM\SYSTEM\CurrentControlSet\Services\WpdBusEnum Contains driver parameters, timeout values, and the Start value (default 3 = Manual). A crucial distinction: MTP (Media Transfer Protocol) vs. USB Mass Storage (UMS) . Less common on Windows 10 than on 7