.MSI - File Extension for Windows Installer Files

What is MSI? MSI, short name for Microsoft Installer, is used as the file extension for Windows Installer files. .MSI files are binary files that can be opened by Windows Installer software. See the sample .MSI file included below.

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File Extension: .MSI

MIME Type: application/x-ole-storage

File Content: Windows Installer

.MSI files are Windows Installer files saved as binary files. Here are the first 64 bytes of a sample .MSI file, au.msi, dumped in HEX values:

d0 cf 11 e0 a1 b1 1a e1 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 3e 00 03 00 fe ff 09 00 ................
06 00 00 00 00 00 00 00 00 00 00 00 03 00 00 00 ................
01 00 00 00 00 00 00 00 00 10 00 00 02 00 00 00 ................
02 00 00 00 fe ff ff ff 00 00 00 00 00 00 00 00 ................
80 00 00 00 00 01 00 00 ff ff ff ff ff ff ff ff ................
ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................

.MSI files are also archive files that can be opened by 7-Zip. Here is the list of contents in the sample .MSI file, au.msi:

           420 !ActionText
            48 !AdminExecuteSequence
            48 !AdminUISequence
            42 !AdvtExecuteSequence
             8 !Binary
            84 !Component
         1,352 !Control
            48 !ControlCondition
           168 !ControlEvent
            72 !CustomAction
           154 !Dialog
           216 !Directory
           520 !Error
            80 !EventMapping
            16 !Feature
            28 !FeatureComponents
           120 !File
           168 !InstallExecuteSequence
            90 !InstallUISequence
            14 !Media
             4 !MsiDigitalCertificate
             8 !MsiDigitalSignature
            40 !MsiFileHash
             4 !MsiPatchCertificate
           160 !Property
            24 !Registry
           264 !TextStyle
           200 !UIText
         3,368 !_Columns
        50,944 !_StringData
         5,440 !_StringPool
           176 !_Tables
        10,152 !_Validation
        79,360 Binary.auutilsDLL
         4,124 Binary.NewBinary9
         1,311 MsiDigitalCertificate.DgtlCert0
         5,493 [5]DigitalSignature
           612 [5]SummaryInformation

.MSI Windows Installer file sample: Click sample.msi to download.

.MSI Windows Installer files can be created and modified by these software: