When you use a locally mapped shared and the IRPStackSize parameter is set too low, you may receive the following error message:

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This behavior can occur in the following operating systems:

•	Windows NT Server 4.0 Service Pack 3 (SP3) or earlier
•	Windows NT Terminal Server 4.0 without Service Pack 4 (SP4)

NOTE: This problem can also occur with service packs after SP3 on Windows NT 4.0 if you install certain software such as Norton AntiVirus software.

Depending on the hardware configuration of the specific computer, the default value may not be large enough for the SRV service to properly administer shared folders on some of the physical drives. You may see one or both of the following event messages:

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Warning This workaround may make your computer or your network more vulnerable to attack by malicious users or by malicious software such as viruses. We do not recommend this workaround but are providing this information so that you can implement this workaround at your own discretion. Use this workaround at your own risk.

Note An antivirus program is designed to help protect your computer from viruses. You must not download or open files from sources that you do not trust, visit Web sites that you do not trust, or open e-mail attachments when your antivirus program is disabled.

For additional information about computer viruses, click the following article number to view the article in the Microsoft Knowledge Base: Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
You can increase the IRPStackSize value. You must first add this value to the following key if it is not already present: Increasing this value requires some memory from the non-allocated memory pool, but the impact should not be noticeable.

NOTE: It is not always advisable to set the IRPStackSize value to its maximum of 12. Generally, you should start the value at 4 and work your way up, increasing the value by 1 each time. The problem may still occur if the value is too high.

This error message may also occur after installing or uninstalling virus-scanning software. You may want to remove the virus-scanning software or increase the IRPStackSize if you need to use the software.

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Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

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The default IRPStackSize for Windows NT 4.0 SP3 and earlier and Windows NT Terminal Server 4.0 is 4. The default value for SP4 is 11.

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For additional information, please see the following article in the Microsoft Knowledge Base: For more information, view the following Symantec Web site: This article provides information on the following products:

Products: Norton AntiVirus 2000, Norton AntiVirus 2001, Norton AntiVirus 5.0 - Windows NT, Norton AntiVirus 5.0 - Windows NT Server, Norton AntiVirus Corporate Edition 6.0, Norton AntiVirus Corporate Edition 7.0
Operating Systems: Windows NT 4.0, Windows NT3.51, Windows NT 4.0 Server, Windows NT3.51 Server. Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.

The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.

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