Mimecast for Outlook - Prerequisites

This article contains information on the prerequisites and installation process for Mimecast for Outlook, including supported operating systems, network requirements, access permissions, Click-To-Run licensing, and key considerations for deployment.

Before You Start

• Mimecast for Outlook must be connected to an Exchange or another email account.
• The Mimecast for Outlook functionality only applies to the primary account configured in Outlook. It doesn't apply to secondary accounts or shared mailboxes, although delegate access can be configured by an administrator for users that maintain another user's Inbox. See Delegate Mailboxes.
• Customers wanting to use Cloud or Domain authentication methods must also configure Two-Step Authentication. Users configured to only use Cloud or Domain authentication will not be able to access Mimecast for Outlook.
• Mimecast for Outlook will only work with machine-based installs; this is not compatible with Online Outlook (OWA) for this please see Mimecast Essentials For Outlook.
• The New Outlook for Windows client does not support COM Add-Ins, including Mimecast for Outlook. Unfortunately, there is no simple migration path to the Office Add-In framework supported by the new Microsoft Outlook client. Microsoft has so far exposed only limited programmatic functionality for their new client and this prevents us from delivering Mimecast for Outlook in its current form.
  See Incompatibility with New Outlook - Nov 2024 for updates on Microsoft's guidance regarding the timeline for moving from opt-in to an opt-out model of the New Outlook for Windows client, and the end of support for the current ‘Classic’ Outlook.

You can download Mimecast for Outlook from the Applications Downloads page.

Operating System

Mimecast for Outlook supports both 32 and 64-bit versions of Office. To install Mimecast for Outlook, run the installation package for the version required. Valid Operating System and Outlook Configurations include:

Software

Requirements

Operating Systems

Windows Server 2019 *

Windows Server 2016 *

Windows 11 *

Windows 10 *

Outlook Versions

Outlook 2021 *

Outlook 2019 *

Outlook 2016 *

Microsoft 365 Apps for Enterprise (formerly Office 365 ProPlus) *

Multi-User Environments **

Terminal Services *

Azure WVD *

Citrix XenApp 7.5 *

Citrix XenApp 6.5 to 7.4 *

Multi-User Environments - SQL Server Versions

Microsoft SQL Server 2016 or later *

MySQL Community Server 5.6.21 *

.NET Framework

The minimum supported .NET versions for Mimecast for Outlook are outlined in the table below. Mimecast supports all later versions of .NET as they are released.

Inbound Check Type	Inbound Check Type
Mimecast for Outlook v7.10 or later	.NET Version 4.5.1

Valid OS and Outlook Configurations

Windows 32-bit with Outlook 32-bit

Windows 64-bit with Outlook 32-bit

* All MfO versions.

** AppV streaming of Mimecast for Outlook is supported as long as the AppV vendor guidance is followed and the environment is set up correctly.

Network Prerequisites

Mimecast for Outlook is an application that utilizes a cloud service. The recommended Mimecast for Outlook environment is where there is a direct route from the client workstation to the internet, or at least to Mimecast services.

Region	API Endpoint	Check for Update URLs
Required	api.mimecast.com	N/A - Used for initial account discovery.
Europe (Excluding Germany)	eu-api.mimecast.com	https://updates-uk.mimecast.com/update/descriptors/mfo/latest
Germany	de-api.mimecast.com	https://updates-de.mimecast.com/update/descriptors/mfo/latest
South Africa	za-api.mimecast.com	https://updates-za.mimecast.com/update/descriptors/mfo/latest
United States of America	us-api.mimecast.com	https://updates-us.mimecast.com/update/descriptors/mfo/latest
Canada	ca-api.mimecast.com	https://updates-ca.mimecast.com/update/descriptors/mfo/latest
Australia	au-api.mimecast.com	https://updates-au.mimecast.com/update/descriptors/mfo/latest
Offshore	jer-api.mimecast.com	https://updates-jer.mimecast.com/update/descriptors/mfo/latest
USB	usb-api.mimecast.com	https://updates-usb.mimecast.com/update/descriptors/mfo/latest

Access Permissions 

The Mimecast for Outlook installer must be run as a user with Local Administrative privileges. The following tables outline the areas of the Registry and File System that the Mimecast for Outlook installer needs access to.

Installation

System Type	Permissions	Location
FileSystem	Write	%programdata%\Mimecast %programfiles% %programfiles(x86)% %CommonProgramFiles%\SYSTEM\MSMAPI\1033 %programfiles%\[Office Installation Directory]\FORMS\1033 %programfiles(x86)%\[Office Installation Directory]\FORMS\1033 %temp% %userprofile%\AppData\Local\Mimecast %AppData%\Local\assembly or %userprofile%\Local Settings\Application Data\assembly %Userprofile%\Documents\Add-in Express\adxregistrator.log
Registry	Write	HKEY_CLASSES_ROOT HKEY_CLASSES_ROOT\MimecastServicesForOutlook.AddinModule HKEY_CLASSES_ROOT\CLSID\FB44DE85-4BF9-4F79-BBAD-F6AEE009F844 HKEY_CLASSES_ROOT\MimecastServicesForOutlook.AddInOptions HKEY_LOCAL_MACHINE\Software\Wow6432Node HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run HKEY_LOCAL_MACHINE\Software\Microsoft\Office\Outlook\Addins

Execution

System Type	Permissions	Location
FileSystem	Read / Write	%programdata%\Mimecast %userprofile%\AppData\Local\Mimecast %userprofile%\AppData\Local\assembly %userprofile%\Local Settings\Application Data\assembly %temp% %programfiles(x86)%\Mimecast %programfiles%\Mimecast
Registry	Read	HKEY_CLASSES_ROOT\CLSID\FB44DE85-4BF9-4F79-BBAD-F6AEE009F844 HKEY_CLASSES_ROOT\MimecastServicesForOutlook.AddinModule HKEY_CLASSES_ROOT\MimecastServicesForOutlook.AddInOptions HKEY_LOCAL_MACHINE\Software\Microsoft\Office\Outlook\Addins

Click-To-Run Licensing

This part outlines guidance relating to deploying Mimecast for Outlook in line with the Microsoft Click-To-Run licensing model. Outlook 2013 and Outlook Microsoft 365 ProPlus use this deployment method.

This applies to:

• Administrators deploying Mimecast for Outlook.
• Where Microsoft Outlook or Microsoft 365 ProPlus is deployed using Click-To-Run deployment.

Considerations

The following guidance is provided in addition to the generic deployment administrator guides:

• Microsoft Outlook must be set as a requirement before deploying Mimecast for Outlook.
• Microsoft Outlook must be fully installed before Mimecast for Outlook is deployed.
• If using a software deployment such as Microsoft SCCM, sequencing should be used to ensure Microsoft Outlook is installed before deploying Mimecast for Outlook.
• Multiple versions of Microsoft Outlook must not be installed side by side (e.g. Microsoft Outlook 2016 Desktop and Microsoft Outlook Microsoft 365 ProPlus). Mimecast for Outlook may not operate correctly if they are.

The New Outlook client does not support COM Add-Ins. For all Mimecast for Outlook features to be enabled, you will need to use the Mimecast Personal Portal, or, the Classic version of Outlook.