Microsoft Online Services Sign-In Assistant 32 or 64 bit?

I had to deploy the MOS SIA for our company and was asking my self OK… I have x64 bit Win 7 machines but Office 32 bit installations. What version of MOS SIA I need to deploy?

System Requirements:

  • MOS SIA can be installed on the following operating systems:
    • Windows 7
    • Windows Vista
    • Windows XP Service Pack 3
    • Windows Server 2008 R2
    • Windows Server 2008
    • Windows Server 2003
  • MOS SIA does not support WOW (Windows-on-Windows) configurations. That is, installing the 32-bit version on a 64-bit operating system is not supported. The 32-bit version must be installed on 32-bit operating systems, and the 64-bit version must be installed on 64-bit operating systems.

So there is the answer. Just install the version corresponding to your Windows version.
Lets look deeper into component overview:
The components of MOS SIA consist of a set of dynamic link library files (DLLs) and a Windows service. These components are called by desktop applications like Office Subscription and Microsoft Lync to authenticate users to Office 365.
The architectural relationship between the components is as follows.

The following binaries are installed in the r %Program Files%Common FilesMicrosoft SharedMicrosoft Online Services location.

  • MSOIDCLI.dll – A file that can be loaded directly by applications that need to authenticate users to Office 365.
  • MSOIDSVC.exe – Installed as a Windows service with the service name msoidsvc. This is the core component that executes the actual logons and service ticket requests to AD FS and Microsoft Online Services authentication servers.
  • MSOIDSVCM.exe – A watchdog process that monitors the MSOIDSVC service. It is launched when the msoidsvc service is started.
  • MSOIDRES.dll – A resource file that contains localized text strings for error messages.

The following additional DLLs are installed on a Windows 7 system.

  • MSOIDCredProv.dll – This is the Windows Credential Provider component that is registered as a COM object in the system.
  • MSOIDSSP.dll – This is the SSP component that is installed in the %windir%system32 folder.

Note: On 64-bit versions of Windows, msoidcli.dll and msoidres.dll are installed in the
%Program Files (x86)%Common FilesMicrosoft SharedMicrosoft Online Services location. On 64-bit versions of Windows 7, msoidcredprov.dll is also installed in this folder.

Registry settings

The following registry keys and values are created or updated as part of the installation of MOS SIA. The data of some values is dependent on installed version and language.
“MSOIDCRLVersion” (RTW version is 7.250.4259.0)
“RemoteFile” (default:

“Flags” (default: dword:00000001)
“Level” (default: dword:00000002)
Note: on Windows 7 systems, the [HKLMSYSTEMCurrentControlSetControlLsaSecurity Packages] string entry gets modified to include an additional string named msoidsspto register the MOS SIA SSP.

Installing MOS SIA

MOS SIA can be installed as follows.

  1. MOS SIA can be pushed to clients in managed environments via a software distribution channel like System Center Configuration Manager (SCCM) or through a third-party desktop software configuration management tool. If a third-party desktop software configuration management tool is being used, then the necessary MOS SIA packages for language and processor will need to be downloaded manually from Microsoft Download Center by the IT Admin.
  2. An end-user runs Office 365 desktop setup and installs most of the required updates and configurations for a computer to work with Office 365. Desktop setup orchestrates the downloading and installation of all Office 365 client components, including MOS SIA. Users in non-managed environments will install MOS SIA through desktop setup.
  3. If an end-user runs a desktop application on their computer that requires MOS SIA, but MOS SIA has not been installed, the application will detect that MOS SIA is missing. The desktop application will alert the user and provide a link to download and install MOSIA.

NOTE: The versions of MOS SIA provided on the Microsoft Download Center are intended for IT Professionals to distribute to managed client systems as part of an Office 365 client deployment via SCCM or a similar software distribution system. Users who install MOS SIA through the Office 365 desktop setup application should not install MOS SIA from Download Center.

Component Servicing (updates)

Updates for MOS SIA are provided through Microsoft Update. Updates can be obtained directly from the Microsoft Update service or in managed environments through Windows Software Update Services (WSUS).