Microsoft KB Archive/911091

= A PlaysForSure device or another Windows Media Player 10-compatible media device does not appear in Windows Media Player 10 even after the device appears to be installed correctly =

Article ID: 911091

Article Last Modified on 5/3/2007

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APPLIES TO

 Microsoft Windows Media Player 10, when used with:  Microsoft Windows XP Professional

 Microsoft Windows XP Home Edition 

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Important This article contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry



SYMPTOMS
Consider the following scenario. You purchase a PlaysForSure device or another Microsoft Windows Media Player 10-compatible media device. You install the device on a Microsoft Windows XP-based computer. In this scenario, the device does not appear in Windows Media Player 10 even after the device appears to be installed correctly.

Additionally, you may notice the following behavior after you install the device:
 * The device displays typical installation progress dialog boxes. These dialog boxes contain messages such as &quot;Device is now installed and ready to use.&quot;
 * The device appears as installed and working correctly under Windows Portable Devices in Device Manager.
 * The device does not appear in My Computer or in Windows Media Player 10. Therefore, you cannot use the device.
 * If you restart or reinstall the device or software, the issue is not resolved.



CAUSE
This issue occurs because PlaysForSure drivers in Windows Media Player 10 depend on specific access permissions to information in the Windows registry. Standard registry access permissions are set in Windows XP that enable this driver to work correctly. If third-party software or a device is installed on the computer, the software or device may incorrectly change these permissions. If the third-party software or driver deletes the Read permission for the Everyone group, the PlaysForSure driver can no longer access the registry. Any device that uses this registry information becomes disabled. Typically, devices that are affected by this issue are devices that communicate with Windows Media Player 10 by using the Microsoft Media Transfer Protocol (MTP).



RESOLUTION
To resolve this issue, change the permissions on specific registry subkeys in the Windows registry. Programs that incorrectly change registry permissions appear to change permissions on either the  or   registry subkeys. Registry subkeys within these subkeys generally inherit their permissions from the  registry subkey. You can restore permissions on these two registry subkeys to reset the permissions on device-specific registry subkeys that are in the  registry subkey. This change restores correct functions to devices that use the PlaysForSure device drivers. To restore the permissions on the  and   registry subkeys, follow these steps:

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk. <ol> Click Start, click Run, type regedit, and then click OK.</li> In the left pane, locate and then click the following registry subkey:

 

</li> Right-click Enum, and then click Permissions.</li> Verify that the Everyone group exists in the Group or user names list.</li> Verify that the Read permission check box under the Allow column for the Everyone group is selected.</li> If the Everyone group does not exist in the Group or user names list, add the Everyone group to this list. Then, enable the Read permission for this group. To do this, follow these steps: <ol style="list-style-type: lower-alpha;"> In the Permission for Enum dialog box, click Add.</li> In the Enter the object names to select box, type Everyone, and then click OK.</li> Under the Allow column, click to select the Read permission check box for the Everyone group, and then click OK.</li> In the Advanced Security Settings for ENUM dialog box, make sure that the '''Inherit from parent the permission entries that apply to child objects. Include these with entries explicitly defined here''' check box is selected. If not, click to select this check box.</li> Click OK, and then click OK to close the Permission for ENUM dialog box.</li></ol> </li> On the File menu, click Exit.</li> Restart the computer.</li> Log on to the computer, and then verify that the device now appears in Windows Media Player 10.</li></ol>

Keywords: kbtshoot KB911091

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