DOCUMENT:Q283217 11-JUN-2002 [winnt] TITLE :Registry Hive Fragmentation Fix May Cause Excessive SAM Size PRODUCT :Microsoft Windows NT PROD/VER::4.0 SP5,4.0 SP6,4.0 SP6a OPER/SYS: KEYWORDS:kbRegistry kbWinNT400PreSP7Fix ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server versions 4.0 SP5, 4.0 SP6, 4.0 SP6a - Microsoft Windows NT Server, Enterprise Edition versions 4.0 SP5, 4.0 SP6, 4.0 SP6a ------------------------------------------------------------------------------- IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base: Q256986 Description of the Microsoft Windows Registry SYMPTOMS ======== The SAM registry hive size in Windows NT 4.0 may increase rapidly after you update your computer with Service Pack 5 (SP5), Service Pack 6 (SP6), or Service Pack 6a (SP6a). CAUSE ===== This problem can occur because the Windows NT 4.0 registry cell allocation behavior reduces SAM fragmentation. This behavior is described in the following Microsoft Knowledge Base article: Q197632 Registry Hive Fragmentation Leads to Excessive Size Although this fix does help to resolve this problem, the fix can increase the SAM size in some situations where there is an excessive number of global groups with many members that rarely change. In this environment, the updated behavior of over-allocating to create larger cells that can be reused for future growth does not work and actually orphans larger fragments, which leads to excessive SAM sizes. RESOLUTION ========== A supported fix is now available from Microsoft, but it is only intended to correct the problem described in this article and should be applied only to systems experiencing this specific problem. This fix may receive additional testing at a later time, to further ensure product quality. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Windows NT 4.0 service pack that contains this fix. To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, please go to the following address on the World Wide Web: http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS NOTE: In special cases, charges that are normally incurred for support calls may be canceled, if a Microsoft Support Professional determines that a specific update will resolve your problem. Normal support costs will apply to additional support questions and issues that do not qualify for the specific update in question. The English-language version of this fix should have the following file attributes or later: Date Time Size File name Platform ---------------------------------------------------- 01/03/2001 05:18p 936,640 Ntoskrnl.exe Intel STATUS ====== Microsoft has confirmed this to be a problem in Windows NT 4.0 SP5. MORE INFORMATION ================ WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk. NOTE: The fix referenced in this article configures SAM cellsize allocation to the original algorithm, but does not enable the user to configure RegistryAdjustCellSize. The fix to allow the registry change described below is included in the following hotfix and should be applied if you need to alter the algorithm behavior. For additional information, click the article number below to view the article in the Microsoft Knowledge Base: Q294345 Registry Hive Fragmentation Behavior Is Not Configurable A registry setting is added to Ntoskrnl.exe to make the Q197632 allocation granularity change optional. To disable the Q197632 allocation granularity setting: 1. Click Start, click Run, type "regedit32" (without the quotation marks) in the Open box, and then press ENTER. 2. Locate and click the following registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control 3. On the Edit menu, click Add Value, and then add the following registry value: Value name: RegistryAdjustCellSize Data type: REG_DWORD Radix: Hexadecimal Value: 0x0 revert to original hive cell allocation granularity, 0x1 use Q197632 hive cell allocation granularity. Default: 0x1 4. Quit Registry Editor. 5. Restart your computer. Additional query words: ntoskrnl 283217 ====================================================================== Keywords : kbRegistry kbWinNT400PreSP7Fix Technology : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400sp6 kbWinNTSEnt400sp5 kbWinNTS400sp6 kbWinNTS400sp5 kbWinNTS400search kbWinNTSEnt400SP6a Version : :4.0 SP5,4.0 SP6,4.0 SP6a Hardware : ALPHA x86 Issue type : kbbug Solution Type : kbfix ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.