You know that moment when someone says, “Can you forward me that email?” and you forward it… and then they say,
“No, the whole email. With the details. And the original attachments. And the mysterious header stuff IT people
whisper about in dark hallways.” That’s where forwarding a message as an attachment comes in.

In Mozilla’s world, this usually means Mozilla Thunderbird, the desktop email client. Thunderbird can
forward an email as a standalone attached file (typically .eml), which preserves the original message
far better than a normal forward. If you’re reporting phishing, documenting a conversation, or sharing a message with
its full context intact, this is the move.

What “Forward as Attachment” Really Does (and Why It’s Useful)

A standard “Forward” typically embeds the original email content into your new message (often called inline).
That’s fine for casual sharinglike “Look at this coupon!”but it’s not always great for accuracy or evidence.

When you forward as an attachment, Thunderbird creates a new email draft and attaches the original
message as a separate file (most commonly an EML file). That attached file can include key technical
details (like message headers) and usually preserves the original formatting and metadata better than inline forwarding.

Reasons people love (and occasionally fear) forwarding as an attachment

• Phishing reporting: Security teams often want the original message intact for analysis.
• Legal/HR documentation: Preserves context, dates, and message structure more reliably.
• Tech support troubleshooting: Helps diagnose spoofing, routing issues, or suspicious headers.
• Multi-email sharing: You can attach multiple emails to one message instead of sending a messy chain.
• Cleaner forwarding: Avoids turning your email into a giant quoted-text lasagna.

Quick reality check: Which “Mozilla” are we talking about?

Mozilla makes several well-known products, but forwarding email as an attachment is a Thunderbird
workflow. (Firefox is a browser, not an email clientunless you time-traveled back to the era of dial-up and
questionable life choices.) If you’re using Gmail, Outlook.com, or another webmail provider, the steps will differ.
This guide focuses on Mozilla Thunderbird on Windows, macOS, and Linux.

Method 1: The Classic “Forward As → Attachment” (Fastest and Cleanest)

This is the most straightforward way to forward a message as an attachment in Thunderbird. It’s also the method most
IT departments quietly hope you’ll use when reporting a suspicious email.

Step-by-step (right-click method)

1. Open Thunderbird and go to the folder that contains the email you want to forward.
2. Right-click the message in the message list.
3. Select Forward As, then choose Attachment.
4. A new compose window opens with the original email attached (often as an .eml attachment).
5. Add the recipient(s), write a short note explaining what you’re sending, and click Send.

Step-by-step (menu bar method)

1. Click the email you want to forward so it’s highlighted.
2. From the top menu, choose Message → Forward As → Attachment.
3. Address your new email and send it.

Pro tip: If you don’t see the classic menu bar on Windows/Linux, tapping Alt often reveals it
temporarily. On macOS, the menu bar is always at the top of the screen.

Method 2: Drag-and-Drop the Email into a New Message (Great for “Attach This While Replying”)

Sometimes you don’t want to create a brand-new forward. You’re already writing an email (or replying to a thread),
and you just want to attach an earlier message like it’s a file. Thunderbird can do that too.

Attach one email by drag-and-drop

1. Open a new message (or start a reply).
2. Go back to your message list and find the email you want to attach.
3. Click and drag that email into the compose window.
4. Drop it near the addressing/header area (around the To/Cc/Subject region or the attachments area),
   not into the body text.
5. The email appears as an attached message (typically an .eml file).

Attach multiple emails at once (the “bundle and send” trick)

1. In the message list, select multiple emails (use Ctrl/Cmd to pick individual ones, or Shift for a range).
2. Start a new email (or open an existing draft/reply).
3. Drag the selected group into the compose window’s header/attachments area.
4. Confirm that each message appears as a separate attachment before sending.

This is especially handy when someone asks, “Can you send me the last three emails from that vendor?”
Instead of forwarding three separate messages (and creating three separate chances to forget one), you can attach them
all to one clean email.

What Your Recipient Sees (and How They Open It)

Most recipients will see something like “Subject.eml” attached to your email. That .eml file is a widely
used email-message format and is often readable by many email clients. In a pinch, it’s also plain-text-based enough
to be opened by text editors (though it’ll look like the email’s DNA sequenceuseful, but not exactly cozy).

Common recipient experiences (no drama required)

• Desktop email apps: Many can open .eml by double-clicking the attachment.
• Webmail: Some providers preview .eml; others require downloading first.
• Security filters: Some organizations block .eml attachments (often for good reasons).

If your recipient says, “I can’t open the attachment,” ask what email system they use. The fix is often as simple as
downloading the file and opening it with an installed email clientor asking their IT team what format they prefer for
forwarded messages.

Troubleshooting: When Thunderbird Doesn’t Behave Like You Expected

Problem: “Everything I forward is suddenly an attachment”

Thunderbird has a setting that controls the default forwarding style: Inline vs As Attachment.
If you prefer normal forwards (inline text) most of the time, check your composition preferences and set forwarding to inline.
You can still use Forward As → Attachment whenever you need the attached-message version.

Problem: “My .eml attachments get rejected or bounced”

Some mail systems treat .eml attachments cautiously, and that can lead to blocks or bounces. If you’re sending to an
organization that blocks EML files, don’t try to “outsmart” their security rules. Instead:

• Ask the recipient (or their IT team) what format they prefer for reporting or documentation.
• Consider forwarding inline if the goal is simply to share readable content.
• For security reporting, many organizations have a dedicated process (a button, a portal, or a mailbox) precisely
  because forwarding methods can vary.

Problem: “Forward As → Attachment isn’t showing up”

First, make sure you’re right-clicking the message in the message list (not a blank spot, not the preview pane).
If the menu bar is hidden, try using the top menu (Message → Forward As → Attachment) after revealing it.
In most standard Thunderbird setups, the option exists even if the interface looks slightly different.

Problem: “The original attachments didn’t come through”

If you forward inline, sometimes certain embedded content or attachments can behave differently depending on how the
original email was built. Forwarding as an attachment often preserves the original structure more reliably,
which is one reason it’s preferred for reporting suspicious emails or documenting evidence.

Best-Practice Scenarios (When Forwarding as an Attachment Is the Right Call)

1) Reporting phishing or suspicious email

Security teams often want the full message intact, including headers, because the “From” line you see is not always
the whole truth. Forwarding as an attachment can help preserve the information needed to investigate routing,
spoofing, and authenticity. When you do this, add a short note like:

“I received this message at 10:42 AM. I did not click any links. Please investigate.”

2) Legal, HR, or compliance documentation

If you’re preserving a record, you want as little accidental editing as possible. Inline forwarding can introduce
formatting changes or selective quoting (even unintentionally). Attached-message forwarding is typically cleaner and
closer to the original record.

3) Customer support and project coordination

Ever had a vendor say, “We never received that request”? Attaching the exact email thread message can reduce ambiguity.
It also lets your teammate open the message in full rather than scrolling through a forwarded wall of text.

Privacy and Safety Notes (Because Emails Contain More Than They Look Like)

Forwarding as an attachment can include more metadata than a normal forwardsometimes including routing information or
identifiers embedded in headers. That’s good for troubleshooting and investigations, but it can also expose details
you didn’t intend to share. Before forwarding:

• Make sure the recipient truly needs the full message intact.
• Remove or avoid forwarding sensitive personal data unless necessary.
• If you’re forwarding for security reporting, use your organization’s approved reporting address or workflow.

FAQ: Quick Answers to Common Questions

Is “Forward as Attachment” the same as attaching a screenshot or PDF?

No. A screenshot or PDF is a static copy. An attached email message (.eml) preserves the original message structure
and often keeps technical details that a screenshot can’t.

Can I forward multiple emails as attachments in one email?

Yes. Select multiple messages, then use Forward As → Attachment, or drag-and-drop the group into a compose window.

What if the recipient can’t open .eml files?

Ask what email system they use and whether they have a desktop client that can open .eml. If not, consider forwarding
inline for readabilityor coordinate an approved alternative format if it’s a compliance/security situation.

Is there a keyboard shortcut for forwarding as an attachment?

Thunderbird includes shortcuts for forwarding in general, but “forward as attachment” is commonly done via the menu
(Message → Forward As → Attachment) or right-click options.

Real-World Experiences People Have with “Forward as Attachment” (Extra Detail)

If you’ve ever watched a group chat explode over a suspicious emailhalf the people yelling “DON’T CLICK IT,” the other
half admitting they already didyou’ve seen why forwarding as an attachment matters. In many workplaces and schools,
the first time someone hears “forward it as an attachment” is during a mini-crisis. The security team wants the
message intact so they can check where it came from, whether it’s spoofed, and what it’s trying to do.

Another common situation: a project handoff. One person goes on vacation (or vanishes into a meeting vortex), and the
next person inherits a thread with “the important email” buried somewhere inside. Forwarding that key message as an
attachment can be cleaner than forwarding an entire chain. The receiver can open the attached email, see the exact
subject line and timestamp, and avoid the confusing “Fwd: Fwd: Re: Fwd:” spaghetti.

People also run into this when dealing with vendors, shipping problems, or billing disputes. Someone asks,
“Can you send the email where they promised X?” Forwarding inline sometimes leads to accidental editsmaybe the
signature collapses, maybe the formatting shifts, maybe the original attachment doesn’t follow along like you expected.
But when the email is attached, it’s closer to sending the original artifact. That tends to reduce arguments like,
“Well, that’s not what it said on our end,” because you’re sharing the message in a form that’s harder to accidentally
alter through forwarding.

There’s also a learning curve moment that shows up all the time: someone forwards a message as an attachment and then
panics because they “can’t see the email” in their own outgoing message. That’s normal. The email is inside the
attachment, not pasted into the body. The best habit is to write a one- or two-sentence note above the attachment:
who sent it, why you’re forwarding it, and what action you want the recipient to take. Without that note, the
recipient might open the attachment and still ask, “Okay… what am I looking at?” (Humans are consistent like that.)

Finally, people discover the “multiple attachments” superpower. Support staff and coordinators often need to send a
short set of related emails to a colleague: “Here are the three messages that show the customer’s request, the
confirmation, and the follow-up.” Instead of forwarding three separate emails (and making the other person hunt through
their inbox), attaching all three to one message can be a neat, self-contained packet. It’s not just convenientit
reduces mistakes, because the recipient gets the full set in one place, in the order you intended.

The big takeaway from all these real-world moments is simple: forwarding as an attachment is less about being fancy
and more about being precise. It’s a way to say, “Here’s the email exactly as it existed,” whether you’re
reporting something suspicious, documenting a decision, or just trying to keep a project from turning into a game of
inbox archaeology.

Conclusion

Forwarding a message as an attachment in Mozilla Thunderbird is one of those small skills that quietly makes you look
like the most organized person in the room. Use Forward As → Attachment when you need accuracy,
cleaner documentation, or when someone (usually IT) specifically asks for the “original email.” For everyday sharing,
inline forwarding is still finechoose the tool that matches the job, and your future self will thank you.