The campaign to convince Apple to fix its annoying Apple Mail URL breakage bug

Apple Mail has an excruciatingly annoying bug related to URLs pasted in emails: in every other mail client, they’re broken and unclickable.


Apparently this is because Apple Mail uses a relatively new email standard, the “delsp” parameter, which supposedly instructs other mail clients to remove spaces inserted in URLs so they can recombine the parts of a URL into one clickable URL again.

Except that’s not really what the RFC says — turns out Apple has incorrectly implemented it.

Josh Simons has written a great blog post explaining why Apple’s implementation is wrong.

I also chanced upon another blog post today that explains how Apple prioritises the fixing of bugs: by the number of duplicate bug submissions reported.

So, I appropriated Josh Simons’ blog post (with plagiaristic apologies) and submitted it to Apple with some additional notes as an “Apple Radar” bug report.

You can submit a Radar report too to encourage Apple to fix this bug. Here’s my submission (after the jump) in case you want copy-and-paste simplicity. You will need to sign up for Apple Developer Connection (free) first to get access to the Radar reporting tool.


Problem report/title:
URLs pasted into email are broken in all other mail clients

Mac OS X

Build number:


Is it reproducable:



The following summary text is originally by John Simonds, posted at

Email sent from Mac OS Mail and read by other mail clients appears to have extra spaces inserted throughout the message, including spaces that break some URLs into two or more pieces, rendering them invalid and unclickable in other mail clients.

Apple’s crime is that it has adopted a relatively new email standard which has not yet been implemented in any other common mail clients like Mozilla Mail, Thunderbird, or Outlook. That would be okay if Apple had made the feature optional, but there doesn’t seem to be a way to turn it off. And, worse, the implementation of the new feature is wrong. Apple shouldn’t be segmenting URLs.

The new feature is the DelSp parameter that is described in RFC-3676. It is used to implement a new way of inserting soft breaks into Text/Plain email that is meant to be flowed (Format=Flowed), the default for Mac OS plain text email when any lines in the message exceed 72 characters. Soft breaks are marked by ending a line with a space, followed by a line break. The message header specifies “DelSp=yes”, which instructs the receiving mailer to logically delete the ending space and the line break. If a URL was broken apart in this way by the sending mailer, the receiving mailer will reconstruct it by removing the intervening space and the line break. Unless, of course, the receiving mailer doesn’t recognize the DelSp parameter, in which case URLs will be split by intervening space and won’t be valid, clickable links.

I said that Apple’s implementation is wrong or at least poorly done because the RFC states the following:

“Regardless of which technique is used, a generating agent SHOULD NOT insert a space in an unnatural location, such as into a word (a sequence of printable characters, not containing spaces, in a language/coded character set in which spaces are common). If faced with such a word which exceeds 78 characters (but less than 998 characters, the [SMTP] limit on line length), the agent SHOULD send the word as is and exceed the 78-character limit on line length.”

While it’s true that the language says SHOULD and not MUST, breaking URLs is really poor form. Apple should fix this problem.

Steps to reproduce:
1. Create a new email in Apple Mail
2. Paste a URL into the email that’s longer than a single line
3. View the email in any other mail client than Apple Mail and notice that the second line of the URL is broken and unclickable

Expected results:
Apple Mail should not break URLs over two or more lines by inserting a space at the end of each line, therefore making the URLs clickable in other email programs.

Actual results:
Apple Mail breaks the URLs over two or more lines by inserting a space at the end of each line, rendering the URLs unclickable in other email programs.

The problem occurs 100% of the time.

Although Apple Mail is supposedly RFC compliant with its DelSp parameter applied to URLs, there are two problems:
1. No other mail clients support the DelSp parameter, making Apple’s RFC compliance impractical
2. Apple is not actually RFC compliant because (as detailed above) the RFC says a generating agent should not insert characters in a single “word” in an email.


If anyone’s interested, my bug submission is number 5116436. Don’t know if anyone but me and Apple can view that link.


3 Replies to “The campaign to convince Apple to fix its annoying Apple Mail URL breakage bug”

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