394298 - Mac OSX Thunderbird Enhancement: "Windows Friendly" Attachments versus Apple Double, Resource Forks

Status: RESOLVED WONTFIX

(Thunderbird :: General, enhancement)

Description

[john]

User-Agent:       Mozilla/5.0 (Macintosh; U; PPC Mac OS X; en) AppleWebKit/419 (KHTML, like Gecko) Safari/419.3
Build Identifier: 

BACKGROUND:

There's a longstanding problem with email attachments sent from Mac email clients showing up for Windows users with additional, mysterious files attached. These are the Mac "resource forks" getting sent as a separate attachment. Apple uses the term "Apple Double files" to describe a pair of files where the resource fork appears as a second file. If you upload a Mac file to a Windows server for example, two files will show up:  MyFile.ext (normal file) plus ._MyFile.ext (resource fork file).

Traditionally with email attachments sent from a Mac (in OS9 Netscape email for example) these resource fork files show up for Windows users with a mysterious name like "Part 1.3" which is even more confusing than "._MyFile.ext". I'm not sure of the Thunderbird handling of this.

Resource fork files have always been completely useless for WIndows users. Today almost all OSX files are cross-platform friendly, and the resource forks hold only cosmetic information such as a custom icon. A Mac user who receives an email attachment without its resource fork can almost always use the file normally anyway.


IMPORTANCE OF ISSUE:

This is a pivotal usability issue for cross-platform email functionality. Windows users get these mystery attachments, can't open them, contact the Mac-using sender (who isn't even aware they're being sent) -- who tries to resend the email, with no improvement. Windows users are often alarmed that the mystery attachment is a virus, and delete the entire email -- scared to open the legitimate attachments (and maybe convinced the Mac user is intentionally sending malware). 

All this has been well known since the late 1990's. Finally, Apple has now implemented at least a basic solution to the problem for its "Mail" client, with what it calls "Windows-friendly" attachments:

http://docs.info.apple.com/article.html?path=Mail/2.0/en/ml1014.html

Meanwhile Thunderbird seems to not even have this central issue for OSX Thunderbird usability on its development roadmap.


GENERAL ENHANCEMENT DISCUSSION:

Obviously the fix to this problem is simply to strip and not send Apple resource fork files (at least by default).

Resource fork files are essentially an anachronism in regards to email attachments, and Apple itself has implemented stripping them for its own email client.

There are several means of achieving this, from more simple to more complex.


IMPLEMENTATION OPTION 1:

OSX Thunderbird always strips Mac resource files. If a Mac user needs to send an attachment to another Mac user with the resource fork intact, they can use a zip archive.

(Zip archiving is already commonly used for sending a folder of files as an attachment, and is integrated conveniently into OSX: right-click on a file or folder and select "Create archive".)


IMPLEMENTATION OPTION 2:

In OSX Thunderbird, Mac Resource files are stripped by default,

There is an item in Thunderbird preferences to alter this behavior:

"[checked by default] Strip Mac resource fork files from email attachments".


IMPLEMENTATION OPTION 3:

In OSX Thunderbird, when the attachments pane appears, there is a checkbox above it (checked by default) that says "Strip Mac resource forks".

Optionally, there is a help question mark icon, which opens a popup that says: "Check to prevent Thunderbird from sending Mac resource fork files which are invisible on Mac but potentially confusing for Windows users. Uncheck if you are emailing a Mac user who reports a problem opening the attachment."

Reproducible: Always

Steps to Reproduce:
1.
2.
3.

Comment 1

[john]

RELATED ISSUES:

These are current bugs about problems with sending resource forks. Note that eliminating resource forks entirely (Option 1 above) solves these issues:

307705

367739

353529

361401

146382

355142 

230223 

115163

Comment 2

[john]

OPTIONAL ADVANCED IMPLEMENTATION:

An address book flag system can be implemented which allows OSX Thunderbird users to specify whether a recipient should get resource forks or not. This is conceptually the same as flagging whether a recipient prefers plain text or HTML email.

Note though that there are usuability problems with this for "Implementation Option 3" above, if there are multiple recipients for the email, with differing address book flags. (How does check box above the attachments pane appear?)

Comment 3

[Klaus Karcher]

(In reply to comment #1)
> RELATED ISSUES:
> 
> These are current bugs about problems with sending resource forks. [...]

Even worse: there are related bugs in connection with *receiving* Attachments with resource forks with Thunderbird /Mac - Intel: the attachments get corrupted. See Bug 398967, Bug 378729 and Bug 462666 (unconfirmed for more than one year, but really serious IMHO)

Comment 4

[Ben Rubinstein]

This continues to bite, to the point that I may have to give up TB and recommend the same to my colleagues.  Even after setting the various arcane preference incantations in the manner recommend in forums, certain files (Word files edited in OpenOffice seem to be a particular culprit - I suspect that they gain resources) are 'attached' as appledouble, inline.

What's particularly poor about the current situation is that TB itself cannot read or display such attachments.  In my sent mail, the message appears with a paperclip icon; when I click on the message, the icon disappears as TB decides that there is no such attachment.  A number of times now I have been made to look like an idiot because the recipient of my message (who may themselves be running TB on Mac) sees me as having failed to attach the document.

As far as I can tell there are no settings which can prevent this demonstrably incorrect behaviour.  It's not just the default settings which are wrong.  There have been reports of this for over seven years now.

Comment 5

[Wayne Mery (:wsmwk)]

iirc we close most of the other Apple Double bug reprts