KERNELBASE.DLL was introduced for Windows 7, mostly from code that was originally in KERNEL32.DLL or ADVAPI32.DLL.

File Version Distribution
6.1 Windows 7
Windows Server 2008 R2
6.2 Windows 8
6.3 Windows 8.1
10.0 Windows 10


The following builds have been inspected for these notes. Most are from MSDN discs. Some, especially since Microsoft greatly reduced its shipment of operating systems on MSDN discs, are from service packs downloaded (typically as self-extracting executables) from a Microsoft website.

Builds are arranged in increasing order of the file version as recorded in the executable’s resources. This version number is readily visible using Windows Explorer either in a so-called infotip for the file or by accessing the Version tab in the Properties dialog for the file. Programmers know this version number as coming from the so-called root block of the version-information resource, specifically from the dwFileVersionMS and dwFileVersionLS members of a VS_FIXEDFILEINFO structure.

The date stamp shown for each version is more obscure. File dates are easily modified after the executable is built and are anyway liable to be shown differently when read from different time zones. However, there is in each executable’s header a date stamp which is set when the executable is built and which is not commonly changed afterwards. It is readily accessible to anyone with programming knowledge and appropriate tools, e.g., Microsoft’s own DUMPBIN utility.

File Version File Header Date Stamp File Size Package
6.1.7600.16385 4A5BDAAE (14th July 2009) 288,256 Windows 7
6.1.7601.17514 4CE7B8F0 (20th November 2010) 288,256 Windows 7 SP1
6.2.9200.16384 5010ACFA (25th July 2012) 756,736 Windows 8
6.3.9600.16384 52158F91 (22nd August 2013) 859,944 Windows 8.1
6.3.9600.17031 530888F8 (22nd February 2014) 863,552 Windows 8.1 Update
10.0.10240.16384 559F3B4C (9th July 2015) 1,529,360 Windows 10

Note the rapid increase in size as ever more functionality—indeed, most of the bread and butter of Windows programming—moves to KERNELBASE from long-established homes in KERNEL32 and ADVAPI32.

64-Bit Windows (amd64)

Microsoft’s distribution of early 64-bit Windows on MSDN discs is even less reliable than is my renewal of subscriptions. I seem never to have received a 64-bit edition of Windows XP. Since a subscription in 2007 produced no x64 build of the original Windows Vista, the copy inspected of that is from an OEM disc. The builds inspected for service packs are from self-extracting executables that have been downloaded from a free Microsoft website (which is, curiously, an order of magnitude faster than downloading disc images from the paid MSDN website).

File Version File Header Date Stamp File Size Package
6.1.7600.16385 4A5BDFE0 (14th July 2009) 421,376 Windows 7
Windows Server 2008 R2
6.1.7601.17514 4CE7C78C (20th November 2010) 419,840 Windows 7 SP1
Windows Server 2008 R2 SP1
6.2.9200.16384 5010AB2D (25th July 2012) 974,336 Windows 8
6.3.9600.16384 5215FA76 (22nd August 2013) 1,115,608 Windows 8.1
6.3.9600.17031 53089862 (22nd February 2014) 1,116,664 Windows 8.1 Update
10.0.10240.16384 559F38C3 (9th July 2015) 1,951,360 Windows 10

The executables for Windows 7 and Windows Server 2008 R2 are identical. This identity is formalised for Windows 7 SP1 and Windows Server 2008 R2 SP1 since Microsoft provides the one self-extracting executable for both product names.

32-Bit Windows on 64-Bit Windows (wow64)

KERNELBASE is sufficiently low-level that its 32-bit executables for 64-bit Windows differ from those of the corresponding 32-bit Windows versions.

File Version File Header Date Stamp File Size Package
6.1.7600.16385 4A5BDBDF (14th July 2009) 269,824 Windows 7
Windows Server 2008 R2
6.1.7601.17514 4CE7BAFA (20th November 2010) 269,824 Windows 7 SP1
Windows Server 2008 R2 SP1
6.2.9200.16384 5010AC2F (25th July 2012) 665,088 Windows 8
6.3.9600.16384 52158F2D (22nd August 2013) 834,048 Windows 8.1
6.3.9600.17031 53088860 (22nd February 2014) 836,096 Windows 8.1 Update
10.0.10240.16384 559F3B2A (9th July 2015) 1,531,376 Windows 10

Where two packages are shown for the same build, the executables are identical.