Fix NS_E_WMP_WMDM_BUSY (0XC00D11A8) - Device In Use

Your portable device is locked by another program or process, so Windows Media Player can't access it. Close the interfering app or kill the background process to free it up.

You're trying to sync music, and Windows Media Player throws NS_E_WMP_WMDM_BUSY (0XC00D11A8) in your face — annoying, right? The error message says the portable device is already in use, and that's exactly what's happening: another program has a lock on your device, and WMP can't get in.

Here's the fix, step by step.

Step 1: Close the obvious culprits

Before you dig into process lists, close these if they're running:

iTunes — yes, even on Windows, iTunes grabs MTP devices and won't let go.
File Explorer windows that are showing your phone or MP3 player's contents. Even a background Explorer window can hold a handle.
Dropbox, OneDrive, Google Drive — if you've set any of them to back up from your device, they'll hold it open.
Any photo import tool — Windows AutoPlay, Photos app, or third-party importers.
Antivirus scans — a scan running on removable media will lock the device.

After closing them, wait five seconds, then hit retry in Windows Media Player. If it syncs, you're done. If not, move on.

Step 2: Unplug and replug the device — properly

Don't just yank the cable. Do this:

Click the Safely Remove Hardware icon in the system tray (bottom-right, near the clock).
Select your device and let Windows confirm it's safe to remove.
Unplug the USB cable.
Wait ten seconds — this matters. Windows needs to release the device handle.
Plug the cable back in. Use a different USB port if you have one, preferably a rear port on a desktop (front ports are often underpowered).

You should hear the Windows device-connect chime, and the device should show up in File Explorer. If it doesn't, the problem is the cable or port, not WMP.

Step 3: Kill the background process that's holding the lock

If closing apps didn't work, something invisible is holding your device. Find it.

Press Ctrl + Shift + Esc to open Task Manager.
Click More details if you only see a small window.
Go to the Details tab (not Processes).
Look for these process names and end them:
wmpnetwk.exe (WMP Network Sharing Service — this one is a repeat offender)
iTunesHelper.exe
AppleMobileDeviceService.exe
Dropbox.exe
OneDrive.exe
explorer.exe (only if you're comfortable restarting Explorer — it'll come back automatically)
Antimalware Service Executable (Windows Defender — pause real-time protection temporarily)
Right-click each one and choose End task.

Now try syncing again in Windows Media Player.

Step 4: Restart the Windows Media Player Network Sharing Service

This service regularly gets stuck and holds device handles. Restart it:

Press Windows + R, type services.msc, hit Enter.
Scroll down to Windows Media Player Network Sharing Service.
Right-click it, choose Restart. If Restart is greyed out, click Stop, wait five seconds, then Start.
Close Services, then close and reopen Windows Media Player.

If you're on a work machine and the service is disabled by group policy, you won't be able to restart it — talk to IT. Home users should have no trouble.

Step 5: Change the USB connection mode on your device

If you're syncing a phone (Android or older Windows Phone), the USB mode matters. MTP works with WMP. PTP (Picture Transfer Protocol) doesn't, and mass storage mode can cause conflicts.

Unlock your phone.
Swipe down the notification shade and tap the USB notification.
Choose Transfer files or MTP. Don't pick "Transfer photos" or "Charge only."
Windows will reinstall the device driver — you'll see a brief notification.
Wait 20 seconds, then retry the sync in WMP.

Why this works

The error code NS_E_WMP_WMDM_BUSY literally translates to "Windows Media Device Manager reports the device is busy." WMDM is the layer Windows Media Player uses to talk to portable devices. It's a single-access API — only one program can hold a device handle at a time. When something else grabs it, WMP gets a busy signal back and shows you 0XC00D11A8.

The processes I listed above are the usual suspects because they all use WMDM or the underlying MTP stack: iTunes for iPod/iPhone sync, Dropbox and OneDrive for camera backup, Windows Defender when it scans removable media, and wmpnetwk.exe because it's actually a separate Windows Media Player process that shares devices across the network.

Restarting the Network Sharing Service clears stale handles that Windows didn't release properly — this happens a lot if you unplug a device while a sync is in progress.

Less common variations

Error appears only on specific devices

If your iPod syncs fine but your Android phone always throws 0XC00D11A8, the phone's USB mode is the issue. Android 8.0 and later default to "Charge only" when you plug in. You have to manually switch to MTP every time unless you enable Developer Options and change the default USB configuration.

Error after a Windows update

Windows 10 version 1809 and Windows 11 22H2 both had bugs where the MTP driver (wpdmtp.inf) got corrupted during the update. Fix: open Device Manager, expand Portable Devices, right-click your device, choose Uninstall device, check "Delete the driver software for this device," then unplug and replug. Windows will reinstall a fresh driver.

Error on a corporate machine with device restrictions

Group Policy can block removable device access entirely, which WMP reports as a busy error. Check with your admin. The policy is under:

Computer Configuration\Administrative Templates\System\Removable Storage Access

Error only when syncing specific files

If it syncs some playlists fine and fails on others, a corrupted media file is the problem, not the device. WMP locks the device, hits the bad file, and never releases the lock. Remove the last few tracks you added to the sync list and try again — when it works, you've found the bad file.

Prevention

Don't sync while backups are running. Schedule Dropbox and OneDrive to run at night when you're not syncing.
Disable WMP Network Sharing if you don't use it. In Windows Media Player, go to Stream menu and turn off "Automatically allow devices to play my media." This stops wmpnetwk.exe from grabbing device handles.
Use Safely Remove Hardware every single time. Pulling the cable mid-sync is the number-one cause of stale handles.
Update your device's USB driver. Check the manufacturer's site — Samsung, Google, and SanDisk all publish MTP drivers that work better than the generic Windows one.
If you sync an iPod or iPhone on Windows, uninstall iTunes if you don't need it. It's the most aggressive device-grabber on the list.

Most people hit 0XC00D11A8 once, fix it by closing iTunes or restarting the Network Sharing Service, and never see it again. If it keeps coming back, it's a driver problem or a background backup tool you forgot was running. Check startup apps in Task Manager — anything set to launch at boot that touches your device is a suspect.