Important This article contains information about how to modify the registry. Make sure to 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:
- You connect a relatively slow removable storage device to a Microsoft Windows Server 2003-based computer or to a Microsoft Windows x64-based computer. For example, this device might be a Magneto-Optical (MO) drive, a compact flash memory device, a USB 1.1 flash memory device, or some other similarly slow device.
- In Device Manager, you set the write cache policy to Optimize for performance on the Properties dialog box.
- You try to perform a disk operation against the device by using an application. Meanwhile, another application is simultaneously writing to the disk.
In this scenario, the operation may take a long time to finish.
The Windows backup utility does not succeed when you use a USB tape drive
For more information about the updates that are included in Windows Server 2003 Service Pack 1, click the following article number to view the article in the Microsoft Knowledge Base:
Method 1: Use the "Optimize for quick removal" write cache policy
Note If you are using SCSI or IDE disks, you cannot select the Optimize for quick removal option for the device. If you are using SCSI or IDE disks, you must use the Optimize for performance option.
To select the Optimize for quick removal option for the device, follow these steps:
- Click Start, click Run, type devmgmt.msc, and then click OK.
- Right-click the device, and then click Properties.
- Click the Policies tab.
- Click Optimize for quick removal, and then click OK.
- Restart the computer.
Method 2: Modify the registry if you cannot use the "Optimize for quick removal" write cache policyIf you are using a SCSI or an IDE disk and cannot use the Optimize for quick removal option, follow these steps:
- Click Start, click Run, type regedit in the Open box, and then click OK.
- Locate and then click the following subkey in the registry: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\<XXX>\<YYY>\<ZZZ>\Device Parameters\ClasspnpNote In this registry subkey, XXX, YYY, and ZZZ are the strings that represent the disk device that you are using.
For example, a sample SCSI MO device might have a Classpnp subkey that is similar to the following:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\SCSI\Optical&Ven_XXXXX&Prod_YYYYY&Rev_0800\4&1faa839c&0&050\Device Parameters\Classpnp
Note if the Classpnp subkey does not exist, you must create it. To do this, click Edit, point to New, and then click Key. Type Classpnp for the name of the subkey, and then press ENTER.
- With the Classpnp subkey selected, click Edit, point to New, and then click DWORD Value.
- Type UserRemovalPolicy for the DWORD name, and then press ENTER.
- Right-click UserRemovalPolicy, and then click Modify.
- In the Value data box, type 3, and then click OK.
- Exit Registry Editor.
- Restart the computer.
If the Optimize for performance option is selected, data that is written by an application is cached by the operation system, and lazy write is used for the cached data.
When a slow device, such as an MO drive or a compact flash memory device, writes data by using lazy write, and you simultaneously try to view files on the device by using an application or by viewing the device status in Device Manager, a delay may occur. You must wait until the lazy writing finishes.
Technical support for Windows x64 editions
Your hardware manufacturer provides technical support and assistance for Microsoft Windows x64 editions. Your hardware manufacturer provides support because a Windows x64 edition was included with your hardware. Your hardware manufacturer might have customized the Windows x64 edition installation with unique components. Unique components might include specific device drivers or might include optional settings to maximize the performance of the hardware. Microsoft will provide reasonable-effort assistance if you need technical help with your Windows x64 edition. However, you might have to contact your manufacturer directly. Your manufacturer is best qualified to support the software that your manufacturer installed on the hardware.
For product information about Microsoft Windows XP Professional x64 Edition, visit the following Microsoft Web site:
Article ID: 904569 - Last Review: Mar 29, 2017 - Revision: 4