# Mozilla Thunderbird Application: MZLA Technologies Also called thunderbird, mozilla thunderbird MZLA Technologies, Productivity Mozilla's mail client. The process is thunderbird.exe. It is separate from Firefox. It is not Outlook. ## What you need to know Thunderbird is thunderbird.exe. Outlook is OUTLOOK.EXE. Firefox is not mail. MZLA's mail client is separate from Firefox. Classic Outlook is the Microsoft sibling. A Thunderbird profile lives under AppData\Roaming\Thunderbird, not Office16. - **What is it?**: Mail client **Still current?**: Yes, see Current status **Official download?**: Use the vendor link in this article Feex says If thunderbird.exe is the mail window, I would not run outlook.exe /safe to test its add-ons. Those are different clients. Firefox is a different exe too. ## What is Mozilla Thunderbird? Mozilla Thunderbird is a desktop mail and calendar client. thunderbird.exe is the Windows process. Classic Outlook is OUTLOOK.EXE. Firefox is firefox.exe. They do not share a profile. ## If you have never used it If you want a desktop mail app that is not Outlook, this is Thunderbird, not Firefox. Download it from thunderbird.net. You add IMAP or Exchange-capable accounts Thunderbird supports. OUTLOOK.EXE is Microsoft's classic mail client. firefox.exe will not read your inbox. MZLA is the Thunderbird company, still in the Mozilla family. ## What is it used for? **IMAP and local folders** Multiple accounts in one window. Outlook profiles and OST files are a different store. **Add-ons from addons.thunderbird.net** Thunderbird extensions. A Chrome Web Store item will not install here. Outlook COM add-ins will not either. **Optional Exchange setups Thunderbird documents** Some work mail still wants classic Outlook. Thunderbird is not OUTLOOK.EXE. ## Who is it for? - People who want mail without a Microsoft 365 Outlook SKU - Users who already have a Thunderbird profile - Anyone who should not open Outlook expecting this add-on set ## Current status Actively developed by MZLA / Thunderbird. This article is the Windows desktop client, not Thunderbird for Android alone. ## How old is it? Thunderbird 1.0 shipped in 2003 as Mozilla's mail companion to Firefox. It is not Outlook 97 and not the 2022 New Outlook package. Firefox remains a separate browser download. ## Versions Major channels first. Exact build numbers are not all verified here. Release ESR Beta ## System requirements Values follow the publisher's public guidance. Workload still changes the real need. ### Minimum | Operating system | A current Windows release Mozilla lists for Thunderbird | | ---------------- | ------------------------------------------------------- | | RAM | Mozilla lists modest RAM. Large local folders want more | ## Resource profile - **CPU demand**: Follows what you open inside the app **RAM demand**: Follows documents, tabs, or libraries ## Installed processes These executables belong to this product when it is installed. | thunderbird.exe | Desktop mail client | | --------------- | ------------------- | ## Startup components Thunderbird can start with Windows from its own setting. That is not Outlook and not Firefox. ## File locations | Typical install | C:\Program Files\Mozilla Thunderbird\thunderbird.exe | | --------------- | ---------------------------------------------------- | ## File formats EML, MBOX, ICS ## Common problems ### People install Firefox when they wanted mail thunderbird.net is this app. mozilla.org/firefox is the browser. Different downloads. ### Work mailbox needs classic Outlook Some tenants require OUTLOOK.EXE, MAPI, or a specific add-in. Thunderbird cannot host those COM add-ins. ## Getting unstuck ### Install from thunderbird.net, not a "Firefox mail" search ad Outlook.com is Microsoft's web mail. It is not this client. ### Open file location on thunderbird.exe Program Files\Mozilla Thunderbird is this product. Office16\OUTLOOK.EXE is classic Outlook. ### Use Thunderbird Safe Mode from Help if add-ons break send That is Thunderbird Safe Mode, not outlook.exe /safe and not Windows Safe Mode. ## Alternatives Classic Outlook, New Outlook, and Windows Mail overlap. Outlook is the Microsoft sibling this article is not. ## Official help and downloads Start with the vendor. Random exe sites are not a support channel. | Download | [www.thunderbird.net/ ](https://www.thunderbird.net/)Official installer or vendor page | | ------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Help | [support.mozilla.org/products/thunderbird ](https://support.mozilla.org/products/thunderbird)Vendor support | | Official site | [www.thunderbird.net/ ](https://www.thunderbird.net/)Start here, not a random exe host | | System requirements | [www.thunderbird.net/en-US/thunderbird/system-requirements/ ](https://www.thunderbird.net/en-US/thunderbird/system-requirements/)Windows versions Mozilla lists | ## Related hardware A large local folder wants disk. Mail send is not GPU work. ## Technical details Technical details Vendor version numbers change. This article does not pin a build. ## Related These entities connect to this article. Type is shown on every link. [Microsoft Outlook: Application](https://feex.it/wiki/software/microsoft-outlook)[How to read Task Manager: Guide](https://feex.it/wiki/software/system/how-to-read-task-manager) ## Sources and verification Reviewed by Feex editorial. Last verified August 2026 Status: Feex Reviewed. [How we research](https://feex.it/wiki/research). - [Mozilla Thunderbird official site ](https://www.thunderbird.net/)· Vendor product page - [Mozilla Thunderbird help ](https://support.mozilla.org/products/thunderbird)· Vendor support - [Thunderbird system requirements ](https://www.thunderbird.net/en-US/thunderbird/system-requirements/)· What Mozilla lists for Windows - [Foxhole process map ](https://foxhole.feex.it/)· First-party samples on Windows PCs. Not a lab benchmark. ## Was this article useful? A yes or no is enough. Pick a reason if you want, or add a short note. Quick facts The short identity of this page. Specs, sources, and the full story stay in the article. - **Developer**: MZLA Technologies **Category**: Mail client **Process**: thunderbird.exe **License**: MPL free software **First released**: 2003 **Official site**: [thunderbird.net](https://www.thunderbird.net/) **Mapped by Feex**: Seen on Windows PCs in Foxhole Feex Reviewed: Last verified August 2026 --- Source: [Canonical Feex Wiki page](https://feex.it/wiki/software/thunderbird/) [Developer guide](https://feex.it/wiki/developers/) | [API policy](https://feex.it/developers/api-policy/) | [Agent guidance](https://feex.it/wiki/llms.txt)