Symptom: Mobile devices using Windows Mobile or Windows CE (HC1, WDT60, WDT90, WDT92, and older models) are seen by Windows in Device Manager under Network Adapters as a Microsoft Windows Mobile Remote Adapter, but do not show up under Portable Devices, and Windows Mobile Device Center fails to recognize that the device is connected.

Cause: Microsoft stopped support and development for Windows Mobile Device Center with Windows Vista. In most cases, you can still load the utility in modern versions of Windows, but as computer manufacturers have been changing their driver software, we are running into more issues with the synchronization process.

Suggestions: Depending on your computer hardware, we have had some success making sure the mobile devices are connected to USB 2.0 ports rather than 3.0, using an external USB hub as a go-between, or using an older machine that is still running Windows 7, which tends to be more compatible with Windows Mobile Device Center. If your computer has an option in the BIOS for enabling Port Debuggers, that may help as well. Check with your computer manufacturer if you are unsure how to view the BIOS or modify settings in it.

Possible solution:

1. Microsoft has released the Media Feature Pack that may restore connectivity to mobile devices. There have been multiple versions of this update. The update is intended for Windows 10 N and Windows 10 KN, but the same feature pack has been shown to resolve this issue in standard Windows 10.

Microsoft has released multiple versions of the update. Despite how they are labeled, some updates are installable on versions of Windows that don't match how they are named. Our recommendation is to download and attempt to install all updates. At each download step, choose the 64- or 32-bit version that corresponds to your version of Windows. Run each update and follow the prompts to allow it to install. Note: If you get a message "This update is not applicable for your PC", move on and try the next update.

KB3010081 Windows 10 version 1503
info: https://support.microsoft.com/en-us/help/3010081/media-feature-pack-for-windows-10-n-and-windows-10-kn-editions
download: https://www.microsoft.com/en-us/download/details.aspx?id=48231

2. After the Media Feature Pack is installed, go to Control Panel > Programs and Features. If present, first uninstall Windows Mobile Device Center Update. If present, next uninstall Windows Mobile Device Center. Reboot if prompted.

Once they are uninstalled, download a fresh copy from the appropriate 32- or 64-bit download link in this KB article:
https://support.microsoft.com/en-us/help/931937/description-of-windows-mobile-device-center

Though Microsoft's article states WMDC is for Windows Vista, the same version is able to be installed in current versions of Windows.

Note for Windows 10 Fall Creators Update (v1709): An additional workaround is necessary; see the following article linked in Related Pages below:
Windows 10 Fall Creators Update (v1709): Windows Mobile Device Center fails to install or uninstall. "There is a problem with this Windows Installer package. A DLL required for this install to complete could not be run..."

3. If the above did not work, try the following. Note that you must have full administrator access on the PC, and the PC must have internet access.

3a. Disable USB Suspend mode on the Windows 10 PC.
3b. Ensure that the device is NOT connecting to a USB 3.0 port. Typically, those ports are colored blue.
3c. With the device connected, open Device Manager and uninstall the Windows Mobile Remote Adapter.
3d. Disconnect the device from the PC and perform a Clean Boot.
3e. Reconnect the device and allow Windows to look for and reinstall new drivers.

Additional Information:

Microsoft's overview page for Media Feature Pack, for Windows 8 & Windows 10
https://support.microsoft.com/en-us/help/3145500/media-feature-pack-list-for-windows-n-editions