Upgrade Mimecast for Outlook

What the Mimecast for Outlook Upgrader does

This Automox Worklet™ detects outdated Mimecast for Outlook installations and upgrades them to a version you specify. The Worklet queries both 32-bit and 64-bit Windows registry hives to find Mimecast installations and compares the installed version against your target version.

Mimecast for Outlook is available in both 32-bit and 64-bit versions to match the Outlook architecture on each endpoint. The Worklet determines which architecture is installed and runs the corresponding MSI installer. This approach requires you to upload both installer files to the Automox console to support mixed environments.

The Worklet examines registry keys including HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall.

The MSI installer runs silently with the /quiet flag, performing an in-place upgrade without user interaction. Endpoints without Mimecast for Outlook installed are marked as not applicable. Endpoints already running the target version or newer exit as compliant.

Why maintain current Mimecast for Outlook versions

Mimecast for Outlook provides email security features including attachment protection, URL scanning, and large file sending directly within the Outlook interface. Outdated versions may have compatibility issues with newer Outlook releases or lack the latest security features and threat intelligence integration.

Keeping Mimecast current maintains protection against phishing attacks, malicious attachments, and other email-borne threats. Version updates often include improvements to threat detection algorithms and user experience enhancements that benefit your security posture.

By uploading specific MSI versions to Automox, you control which version deploys across your environment. This lets you test new releases in a pilot group before wider deployment, reducing the risk of compatibility issues affecting productivity.

How Mimecast for Outlook upgrades work

1. Evaluation phase: The Worklet searches HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall (32-bit) and the 64-bit registry hive for entries matching "Mimecast for Outlook". It compares each installation's DisplayVersion against $AppVersion. If any installed version is lower than the target, the endpoint is flagged for remediation. Endpoints without Mimecast exit as not applicable.

2. Remediation phase: The Worklet re-checks both registry hives to determine which architecture needs upgrading. For 64-bit installations found in the 64-bit hive, it runs the 64-bit MSI ($64bitFilename). For 32-bit installations, it runs the 32-bit MSI ($32bitFilename). Both use Start-Process with /quiet and -Wait for silent, synchronous installation.

Mimecast for Outlook upgrade requirements

• Windows 7 or later with Microsoft Outlook 365 or compatible version

• Mimecast for Outlook already installed (Worklet only upgrades existing installations)

• Upload both 32-bit and 64-bit MSI installers to the Automox console

• Configure $AppVersion with target version number (e.g., '7.9.0.79')

• Configure $32bitFilename and $64bitFilename with exact installer filenames

• Download installers from Mimecast Community: https://community.mimecast.com/s/mimecast-for-outlook

Expected Mimecast plugin state after upgrade

After successful remediation, Mimecast for Outlook runs the target version you specified. The registry DisplayVersion reflects the new version. Users see updated Mimecast functionality in their Outlook ribbon without needing to restart Outlook in most cases, though a restart may be required for some feature updates.

If installation fails, the Worklet exits with code 1 and outputs "Installation failed". Common issues include incorrect installer filenames, missing MSI files in the console payload, or file-in-use conflicts with Outlook running during the upgrade. Close Outlook before running the Worklet or schedule during off-hours for best results.

How to validate upgrade mimecast for outlook changes

1. Run this Worklet on a pilot Windows endpoint and review evaluation output for upgrade mimecast for outlook.

2. Confirm Automox activity logs show successful completion and exit code 0.

3. Verify endpoint state using checks aligned to evaluation script logic, such as Get-ChildItem, Get-ItemProperty, Where-Object.

4. Validate remediation effects from script operations such as Split-Path, Write-Output, Start-Process, then rerun evaluation for compliance.