All external drive devices are set to read-only unexpectedly after you set an embedded CD or DVD device to read-only in Windows 7 or in Windows Server 2008 R2

Assume that you have a computer that is running Windows 7 or Windows Server 2008 R2. You use an application to set an embedded CD or DVD device or an embedded CD or DVD drive to read-only. Then, the Deny Write permission of the device is applied to everyone who uses this computer. In this situation, all the external drive devices are also set to read-only unexpectedly.

Note The application uses the SetKernelObjectSecurity�function to change the system access control list (SACL) for the embedded CD or DVD device.

This issue occurs because writer objects and registry entries for the CD or DVD devices cannot be created as expected. When you connect an external CD or DVD device is added to a computer, Windows Explorer examines if it is a writable device. Then, Windows Explorer creates internal writer objects and registry entries that reflect the attribution of the device. To do this, Windows Explorer enumerates all the connected devices in a loop, and then Windows Explorer creates writer objects and registry entries for the writable devices. When a CD or DVD device that has Deny Write permission set on its device object, Windows Explorer cannot create a writer object on the device. Therefore, the enumeration loop stops unexpectedly and Windows Explorer cannot enumerate the rest of the devices. Writer objects and registry entries for the rest of the devices cannot be created. Therefore, all the other drive devices are treated as read-only devices.

Usually, Windows Explorer performs the enumeration for the devices one by one. The device that is affected by this issue depends on its position in the enumeration sequence. The devices that are enumerated before Windows Explorer starts to enumerate the device that is set to read-only as described in the "Symptoms" section are not treated as read-only devices. But the embedded CD or DVD device is the first to be found in the enumeration sequence. Therefore, when an embedded CD or DVD drive is set to read-only, all the external devices are affected regardless of the order.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix, you must be running one of the following operating systems:

• Windows 7
• Windows 7 Service Pack 1 (SP1)
• Windows Server 2008 R2
• Windows Server 2008 R2 Service Pack 1 (SP1)

For more information about how to obtain a Windows 7 or Windows Server 2008 R2 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

Registry information

To apply this hotfix, you do not have to make any changes to the registry.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.

Windows 7 and Windows Server 2008 R2 file information notes

Important Windows 7 hotfixes and Windows Server 2008 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 7/Windows Server 2008 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.

• The files that apply to a specific product, SR_Level (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:

  Version	Product	Milestone	Service branch
  6.1.760 0.21xxx	Windows 7 and Windows Server 2008 R2	RTM	LDR
  6.1.760 1.22xxx	Windows 7 and Windows Server 2008 R2	SP1	LDR

• The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows 7 and for Windows Server 2008 R2" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintaining the state of the updated component. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

For all supported x86-based versions of Windows 7

For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

For all supported IA-64-based versions of Windows Server 2008 R2

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information about the SetKernelObjectSecurity function, go to the following Microsoft website: For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

Additional file information

Additional file information for Windows 7 and for Windows Server 2008 R2

Additional files for all supported x86-based versions of Windows 7

Additional files for all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

Additional files for all supported IA-64-based versions of Windows Server 2008 R2