Administrator setup for GSSMO

G Suite Sync for Microsoft Outlook

If you have the legacy free edition of G Suite, upgrade to G Suite Basic to get this feature. 

This article is for G Suite administrators. To begin using GSSMO, go to GSSMO User Help.

You can set up G Suite Sync for Microsoft® Outlook® (GSSMO) for users in your organization so they can synchronize their email, calendar, and contact data between G Suite and Outlook.

Before you begin installation and setup, make sure you meet the system requirements.

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System requirements

G Suite requirements

This feature is available with G Suite Enterprise, Business, Basic, G Suite for Education, and Nonprofits edition. For details, go to Compare editions.

Operating system and Outlook requirements for client machines

Note: As Microsoft® no longer actively supports the platforms, support for Windows® XP and Server 2003 in our data migration and sync products was stopped on December 31, 2018. Learn more

Operating system requirements

  • Windows Vista SP1 (32 and 64 bit)
  • Windows 7 (32 and 64 bit)
  • Windows 8 (32 and 64 bit)
  • Windows 10 (32 and 64 bit)

Regardless of which version of Windows you are using, we recommend you upgrade to the latest patches for that version.

Note: GSSMO isn't supported for Apple® Mac®. Microsoft Outlook for Mac doesn't support the Messaging Application Programming Interface (MAPI), which GSSMO needs to communicate with Outlook.

Outlook requirements

  • Microsoft Outlook 2003 SP3
  • Microsoft Outlook 2007 SP2 (or SP1 with hotfix)
  • Microsoft Outlook 2010 (32 and 64 bit) with Service Pack 2
  • Microsoft Outlook 2013 (32 and 64 bit)
  • Microsoft Outlook 2016 (32 and 64 bit)
  • Microsoft Outlook 2019 (32 and 64 bit)

Note: Microsoft Outlook 2003 and Microsoft Outlook 2007 are no longer actively supported by Microsoft. We recommend you upgrade to a supported version of Microsoft Outlook.

Permissions for users

In order to install GSSMO, users must have local administrator permissions for their machines.

Port requirements

Open port 443 for the following applications on each client machine:

  • Outlook.exe
  • ProfileEditor.exe


GSSMO uses HTTPS to connect to Google services using a proprietary GSSMO-specific Gmail sync protocol. It also uses the following APIs:

GSSMO does not use IMAP or SMTP.

Set up and install GSSMO

Step 1: Set up GSSMO in the Google Admin console

Turn on the following features in your Admin console:

  1. Sign in to the Google Admin console.
  2. Turn on GSSMO for your account:
    1. From the dashboard, click Appsand thenG Suiteand thenGmailand thenEnd User Access.
    2. Click G Suite Syncand thencheck the Enable G Suite Sync for Microsoft Outlook for my users box.
    3. Click Save.
  3. Turn on the Google Calendar service (so users can create profiles). For details, go to Turn Calendar on or off for users.
  4. To use the Global Address List (GAL) Generator:
    1. From the Admin console Home page, go to Securityand thenAPI Permissions.
    2. To grant G Suite Admin API access, next to Admin, click Enable.
    3. Click Save.
  5. Turn on contact sharing (so users' Global Address Lists are dynamically updated):
    1. From the Admin console Home page, go to Menu and thenDirectoryand thenDirectory settings.
    2. Click Sharing settingsand thenContact sharing.
    3. Select Enable contact sharing.
    4. Click Save.
  6. Turn on the Drive service and Drive apps (required to synchronize notes to Drive):
    1. To turn on Drive, go to Turn Drive on or off for users.
    2. To allow users to install Drive apps, click Appsand thenG Suiteand thenDrive and Docsand thenFeatures and Applications.
    3. Click Drive SDKand thencheck the Allow users to access Google Drive with the Drive SDK API box.
    4. Click Save.
Step 2: Install GSSMO

Users in your organization who want to sync their data between G Suite and Outlook must have GSSMO installed on their client machine. There are 2 options for installation.

Option 1: Push an MSI file to your users

To do this, download the MSI file from the GSSMO download page. Be sure to pick the correct edition (32 or 64 bit) for your users' version of Outlook.

You can then push the MSI file to your users with the software you use to deploy and secure your organization's applications.

Your users can then follow these instructions to install the file.

Option 2: Let your users download and install GSSMO themselves

Your users can download the EXE file from the GSSMO download page.

They can then follow these instructions to install the file.

Install location

The default location on each client machine is C:\Program Files\Google\Google Apps Sync.

Step 3: (Optional) Set up free/busy information for Exchange users

If you're using GSSMO in a mixed G Suite and Microsoft Exchange environment, and you want to query availability information for Exchange users, you need to:

  1. Install and configure Google Calendar Connector Web Service. For instructions, go to Google Calendar Connector Web Service Installation and Configuration Guide.

    Important: When you set up the web service, make sure you do not set up the Google Calendar Connector Sync Service.

  2. Create the following registry key and accompanying string value on each client machine where GSSMO is installed. If you're running a 32-bit version of Outlook on a 64-bit version of Windows, create this registry key in the correct location for 32-bit applications. For details, consult these instructions on using the Windows registry at Configure options through the registry.
    • Registry key— HKEY_CURRENT_USER\Software\Google\Google Apps Sync\CalendarSync
    • String value—Value name: FreeBusyURL; Value data: <URL for the Calendar connector>

      Example (where you replace MY_COMPANY_FREEBUSY_SERVER with the name of your company's server)

Note: Google Support cannot assist with troubleshooting your Google Calendar Connector Web Service installation.

Import data

Integration with G Suite Migration for Microsoft Outlook

With GSSMO, your users can import data from an Exchange account or Outlook PST file. To do this, GSSMO uses a separate migration tool, G Suite Migration for Microsoft Outlook (GSMMO). GSSMO launches the GSMMO migration tool automatically and, in most cases, users won't even notice they're using a separate tool.

GSSMO launches the migration tool when the user:

GSMMO as a standalone migration tool

Users can launch GSMMO as a standalone application. In the Start menu, click G Suite Migrationand thenG Suite Migration for Microsoft Outlook.

However, this tool doesn't import Outlook notes, tasks, or journal entries. To import this data, users should run GSSMO.

How do I install the migration tool?

The GSMMO migration tool must be installed on each client machine.

Users who download and install GSSMO themselves (Option 2 above) install the GSMMO migration tool automatically.

If you push GSSMO to users via an MSI file (Option 1 above), you will also need to push the GSMMO migration tool to them as well. Or, have them install the GSMMO migration tool themselves. For details, go to Install GSMMO.

What's imported?

Users can sync email, contacts, calendar events, and Outlook notes, which are then available in Outlook and the G Suite web interface.

Outlook tasks sync to G Suite but only after GSSMO starts. (Email, contacts, and calendar events sync while importing.)

Outlook journal entries are not synchronized to G Suite, but users can import them from their Outlook profile during the initial sync.

Get help

The Google Cloud Support Center can provide support for GSSMO and GSMMO, but not for Outlook or Windows. If you have additional Outlook or Windows questions, please consult your Microsoft documentation.

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