Cannot Install Service Pack 6/6a with High Encryption Internet Explorer

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The information in this article applies to:

Microsoft Windows NT Workstation versions 4.0 SP6, 4.0 SP6a
Microsoft Windows NT Server versions 4.0 SP6, 4.0 SP6a
Microsoft Windows NT Server, Enterprise Edition versions 4.0 SP6, 4.0 SP6a
Microsoft Windows NT Server version 4.0 SP6, Terminal Server Edition

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SYMPTOMS
If you attempt to install the standard-encryption (or 56-bit) version of Windows NT 4.0
Service Pack 6 or 6a on a Windows NT 4.0-based computer that already has Microsoft
Internet Explorer High Encryption Pack or Internet Explorer version 5.5 installed,
you receive the following error message:

You have chosen to install a version of the Service Pack with Standard Encryption
onto a system with High Encryption. This is not supported. To successfully install
this version of the Service Pack, you must install the High Encryption version.
Press Help for more information about obtaining the High Encryption Version of this
Service Pack. Service Pack Setup will now exit.

CAUSE
This issue occurs because the Schannel.dll file that is installed by Microsoft Internet
Explorer High Encryption Pack and Internet Explorer 5.5 cannot be overwritten by the
service pack installation program.

Internet Explorer 5.5 includes 128-bit encryption by default because of the United
States government's recent decision to allow companies to export products that use strong,
128-bit encryption.

Windows NT 4.0 Service Pack 6 and 6a were released before this decision was made. Therefore,
localized versions of Service Pack 6 and 6a are 40-bit versions. 40-bit versions of these
service packs detect higher encryption levels and do not allow themselves to be installed.

RESOLUTION
To work around this issue and prevent the version-number scanner from comparing the
Schannel.dll file versions:

Use any text editor (such as Notepad) to open the Update.inf file in the
I386\Update folder in the service pack source files.

Place a semicolon (;) before the reference to the Schannel.dll file in the
[CheckSecurity.System32.files] section of the Update.inf file.

Save and then close the Update.inf file.

Install the service pack.

Additional query words: 56 bit sp6 sp6a

Keywords : kberrmsg kbsetup
Issue type : kbprb
Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400search kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400sp6 kbWinNTS400sp6 kbWinNTS400search kbNTTermServ400sp6 kbNTTermServSearch kbWinNTW400sp6