System Requirements

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The calculator below helps to specify the hardware needs subject to the number of users, stored email, and the archiving strategy.

Calculations are based on the following base values:

  • Yearly Email Volume per User: 10000
  • Email Size: 75Kb
  • Compression Ratio: 60%
Total Number of Users
Total Number of Instances
Years of Email Data
Archiving Strategy
Processor (Cores/Threads) /
Main Memory
Disk SpaceOperating System
Search Indexes
Network Bandwidth1000 Mbit/s

Please note: For a planned MailStore Server installation with more than 2000 users, please contact our Technical Support to determine the optimal hardware setup.


Operating System

MailStore Server, MailStore Client and MailStore Outlook Add-in require the following operating systems for installation and execution. Both 32-bit and 64-bit versions are supported.

  • Microsoft Windows 11
  • Microsoft Windows 10
  • Microsoft Windows Server 2022 (Essentials, Standard, Datacenter, Datacenter Azure Edition)
  • Microsoft Windows Server 2019 (Essentials, Standard, Datacenter)
  • Microsoft Windows Server 2016 (Essentials, Standard, Datacenter)

Please note: For a MailStore Server installation with more than 25 users, a Microsoft Windows Server operating system is required for the MailStore Server Service because of restrictions of concurrent connections of Microsoft Windows client operating systems.

Other Software

The following other software is required:

  • Microsoft .NET Framework Version 4.8
  • Optional: IFilter drivers on the MailStore Server computer for filetypes to be indexed

Outlook Versions

MailStore Outlook Add-in is compatible with the following versions of Microsoft Outlook for Windows. Both, 32-bit and 64-bit versions are supported.

  • Microsoft Outlook 2021 (Click-to-Run only, Windows Store version is not supported)
  • Microsoft Outlook 2019 (Click-to-Run only, Windows Store version is not supported)
  • Microsoft Outlook 2016 as component for Office 365 (Click-to-Run)
  • Microsoft Outlook 2016
  • Microsoft Outlook 2013 as component for Office 365 (Click-to-Run)
  • Microsoft Outlook 2013
  • Microsoft Outlook 2010 (Click-to-Run is not supported)
  • Microsoft Outlook 2007
  • Microsoft Outlook 2003
Important Notice: Outlook 2003, 2007 and 2010 are no longer maintained by Microsoft. Therefore, we are only able to ensure limited compatibility and thus provide limited technical support for Outlook 2003, 2007 and 2010. Information in this document regarding MailStore's capabilities towards Outlook 2003, 2007 and 2010 is no longer maintained and may no longer be up-to-date. Furthermore, we reserve the right to partially as well as completely remove support for Outlook 2003, 2007 and 2010 in a future MailStore update.

Web Browsers

The following web browsers are officially supported by MailStore Web Access. Other browsers based on the same rendering engine as the once below (e.g. Opera) may work as well.

Operating System / Browser Edge Firefox (Latest) Chrome (Latest) Safari (Latest)
Windows 10 Supported Supported Supported
Windows 8.1 Supported Supported
Windows 7 (SP1) Supported Supported
macOS Supported Supported Supported
Linux Supported Supported

Frequently Asked Questions

Email Volume

Q: How do large email volumes affect the performance and what is recommended maximum?

A: The more emails are archived on a daily basis the more resources are required and more time is needed to execute certain tasks such as searching the archive. Environment with much higher volumes than 10000 emails per user per year, may experience degraded performance over time.

Dedicated machine

Q: Can I install MailStore Server on the same computer where Microsoft Exchange or any other email server is installed or do I have to install it on a dedicated machine?

A: Primarily this depends on the size of your setup, the archiving strategy and the kind of usage. Whenever possible, the MailStore Server service should be installed on a dedicated machine.

Database server

Q: Most email archiving products on the market seem to require Microsoft SQL Server or a similar product installed. Does MailStore Server also require an external database server?

A: MailStore Server comes with an integrated storage and does not depend on any other external database server.

Web server

Q: Do I need an additional web server like Microsoft IIS or Apache to offer MailStore Web Access to my clients?

A: No. MailStore Server runs its own HTTP server on the corresponding TCP ports. Therefore you do not need an additional web server to use MailStore Web Access.

Anti-Virus Software

F: What needs to be considered while using anti-virus software with MailStore?

A: When using file based virus scanners, it is recommended to exclude all archive directories (master database and archive stores) from scanning. For more information, please refer to the notes on anti-virus software.


Q: Is it possible to run MailStore Server on virtual machines like VMware guests or similar?

A: MailStore does not provide any tested and approved virtual machine image for virtualized platforms. Yet, it is generally possible to install and operate MailStore Server in a virtual environment.
When running a virtual machine, keep in mind, that the system requirements (hardware and software requirements) must be met at all times in order to ensure a stable and efficient operation. For example, in a hosted virtual server environment, servers with exclusively dedicated resources should be used instead of servers that share their resources with other machines.
It is mandatory to reserve appropriate compute and storage resources. In addition, such VM shall be deployed with on-premises hardware, not in public cloud environments.
If a virtual machine is stopped, MailStore must either be frozen via VSS or the entire virtual machine including data storage must be stopped consistently. For more information, see the Backup and Restore article.
Please note that MailStore cannot provide technical support for the configuration and operation of your virtualization system. Any application failure reported to MailStore must be reproduced on physical hardware in case of doubt.

Terminal Server environments

Q: Is it possible to run MailStore in a terminal server environment?

A: Yes, running MailStore Client and MailStore Outlook Add-in is absolutely possible. Running MailStore Server service on a terminal server is not recommended.

Network Attached Storage

Q: Do I have to store the archive on the local hard disk, or can I also store it (or parts of it) on network attached storage, e.g. a network share?

A: In general, using local storage is preferable to using network storage. To use MailStore Server with storage on a NAS, different options are available which are described in the article Using Network Attached Storage (NAS).