Why does Outlook use a semicolon to separate multiple recipients by default?


Microsoft Outlook by default uses a semicolon to separate multiple recipients. You can change this to a comma, but why is the semicolon the default?

Microsoft Outlook was originally positioned as a business product, and many businesses complained that the use of a comma as a separator created havoc because they have a policy of setting names in the address book as "Last, First".

In 2000, the Outlook folks tried to change the default, but the outcry from corporations made them go back to having the semicolon be the default separator.

Besides, there are a lot of people who have commas in their names, such as Martin Luther King, Jr.

Comments (35)
  1. Boris says:

    I just opened Outlook 2013 and reproduced the reason I never thought about this before: both the Auto-Complete List and the Global Address List insert semicolons automatically.

  2. Andrew says:

    Ooh, relevance points for the name/date combo!

  3. asdf says:

    OT but; Why is semicolon the separator in %Path%? Semicolon is valid in folder names, should have used something like | or *…

  4. DWalker says:

    And probably everyone who works at Microsoft used Last, First as the way to display contact names. I say this because in all versions of Outlook before Outlook 2007, if you set the display format to "First Last" it would not stick. A reboot, or adding a new contact, or just a sneeze would change the setting back to "Last, First". And half of my contacts would show as "Last, First" while the other half would show the way I specified.

    My conclusion from that situation was that none of the Outlook developers and testers used "First Last" as the display format, or they would have noticed it. (And I did not have a support contract, so I couldn't enter a bug.)

    [The default at Microsoft is "First Last". Maybe your IT department is messing with you. -Raymond]
  5. Grzechooo says:

    @asdf

    You can quote folder names in PATH (I've just discovered this).

  6. Interessting…

    I am thinking about it some times, but I never thought about a deeper Background. But for those things, I love this blog :)

  7. asdf says:

    @Grzechooo: Is this documented anywhere and how far back is it supported?

  8. John Ludlow says:

    And what about those people who have semicolons in their name, eh? http://xkcd.com/327/

    ;)

  9. Kufat says:

    @asdf: The format of the PATH environment variable predates semicolons being allowed in file/directory names.

  10. Ken Hagan says:

    Quotes in PATH were certainly supported on WinXP. I would guess that they've been supported ever since long names came along.

  11. dave says:

    > Why is semicolon the separator in %Path%?

    Because it's half-way to being the same as Unix.

    $ echo $PATH

    .:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

    [And it couldn't go all the way because : is valid in paths (it's the drive letter indicator). -Raymond]
  12. Gabe says:

    Of course a colon is valid in Unix paths, too. The big difference is that approximately 100% of Windows (and DOS) paths have a colon in them, while approximately 0% of Unix paths have a colon in them.

  13. Nico says:

    Personally, I prefer using a semicolon as a separator as it seems to be a "more special" character than the comma.  As you point out, a comma might be found in a person's name, but (considering PATH) it also seems to be more common in file paths as well.

    Regarding Last, First — that's one of those things that seems like a good idea when you're planning an Active Directory deployment, but as someone who's worked with both Last, First and First Last environments, just using the default First Last can save you a lot of headache in both administration and usability.  Really, all that Last, First gives you is a little better default sorting in AD tools like Users and Computers (and that can be achieved easily enough through other means).

  14. someone says:

    @dave + Raymond,

    Fun fact:

    Colon is a valid character in a Unix directory name and makes such directories impossible to encode in $PATH

  15. "In 2000, the Outlook folks tried to change the default…"

    Why?

    [Because of feedback from people who said "Outlook should accept commas to separate addresees." -Raymond]
  16. cheong00 says:

    As programmer, using semi-colon as separator is just plain natural choice to me. Even in Excel formulas, sometimes when we need to concatenate multiple text fields, semi-colon is still the natural choice.

    I didn't have second thought when seeing Outlook using it as separator of email addresses.

  17. Dave says:

    Finally an explanation for why Outlook is different to every other email app on the planet.  That does however lead to a followup question: If every other email app on the planet doesn't have problems with commas, why is it such a big deal for Outlook?

    (Also, the fix via a config-option change only works for Outlook as an application.  If you have to use the web interface, there's no way to fix it, you have to manually re-type your address line if you're cutting and pasting into Outlook).

    [What happens in every other email app if you type "Smith, Bob, Jones, Jane" in the To field? -Raymond]
  18. cheong00 says:

    @Dave: I could guess that it could be because of the fact that Exchange works with Active Directory, and by default the proxyAddresses attribute contents are separated by semicolon. This makes it natural choice to use it too as separator.

  19. moo says:

    @Dave If Outlook worked the same as every other email app then what would be the reason to use Outlook?

  20. '[Because of feedback from people who said "Outlook should accept commas to separate addresees." -Raymond]'

    Interesting. :) Feedback by whom?

  21. ender says:

    @cheong00

    > As programmer, using semi-colon as separator is just plain natural choice to me. Even in Excel formulas, sometimes when we need to concatenate multiple text fields, semi-colon is still the natural choice.

    Switch your locale to something that uses , as decimal separator, and Excel will start using semicolons as formula separators.

  22. Boris says:

    I just realized that this entry was subtly posted in honor of the Martin Luther King, Jr. Day of Service.

  23. Skyborne says:

    @Gabe: "Of course a colon is valid in Unix paths, too."

    Nope, it's actually not, at least for bash.  None of the obvious quoting methods work, then 10 seconds on the internet turned up this StackOverflow question: stackoverflow.com/…/how-to-escape-colon-in-path-on-unix

    Given how widespread bash is (hi, shellshock bug), if it isn't supported on bash, it's effectively not supported…

    Bonus on-topic chatter: the email RFCs specify syntax for "group-name: address, address, address;" using the semicolon to separate the groups.  That's how "Undisclosed-recipients:;" works.  It's a "non-empty" value for the To field to prevent the MTA from choking, which enables putting all of the real recipients into Bcc.

  24. Joshua says:

    Considering that everything but slashes and nulls are valid in UNIX filenames, I wonder how one would avoid it.

  25. John Elliott says:

    Obviously using punctuation in this way is entirely wrong. Outlook (and PATH) should be using U+001F INFORMATION SEPARATOR ONE between elements. Or perhaps PATH should use U+001E INFORMATION SEPARATOR TWO, with U+001F used between each directory in a path. To our time machines!

  26. DWalker says:

    @Raymond:  Sorry, I made an assumption.  I'm glad the issue appears to be fixed in Outlook 2007 and above, but "my IT department" has never applied group policy to my computer, so they couldn't mess with me….  (At my previous job, I WAS the IT department, and at my current job, my computer doesn't get group policy applied.)

  27. Evan says:

    @Skyborne: "Nope, it's actually not, at least for bash"

    Bash has no problems with :s in paths ('mkdir :', 'cd :', 'cd ..', 'rmdir :' works fine), you just can't escape it in $PATH (or probably $LD_LIBRARY_PATH and other similar variables). Those are two different things, and Gabe was talking about the former.

  28. Joshua says:

    @John Elliott:

    Time machine initialized. Loop closure failed due to cascade of the following form: Using U+001F as list separator resulting in keyboard adding U+001F followed by U+001F valid in filenames followed by initializing a time machine to correct the mistake.

  29. Skyborne says:

    @Evan: bash doesn't interpret any of those as colon-separated lists, either.  They're just arguments to mkdir/rmdir, and filenames to cd.

    With all the talk about $PATH/%PATH%, it seems I just assumed Gabe was referring to the same thing.

  30. Evan says:

    @Skyborne: "bash doesn't interpret any of those as colon-separated lists, either. "

    Sure. Gabe didn't say "colon-separated lists."

    "With all the talk about $PATH/%PATH%, it seems I just assumed Gabe was referring to the same thing."

    Try this elaboration: "Of course a colon is valid in Unix paths, too. The big difference is that approximately 100% of Windows (and DOS) paths have a colon in them, while approximately 0% of Unix paths have a colon in them. As a result, Windows/DOS needs to handle :s gracefully (e.g. by using a different character), whereas the rarity of : paths in Unix means if they don't work in $PATH it's not a huge loss."

  31. moo says:

    @evan

    Yes it's obvious that the "colon is valid in Unix paths, too" refers to paths passed to calls like open() & mkdir() and not PATH= handling. Using the PATH= interpretation would make "0% of Unix paths have a colon in them" a lie.

    It's irrelevant what any modern unix system does though, the characters for separators were chosen many years ago.

  32. Dave says:

    @Raymond

    >What happens in every other email app if you type "Smith, Bob, Jones, Jane" in the To field

    In the one I use, it looks up each of the four names and tries to deliver to them.  If I want to send mail to Bob Smith I type in "Bob Smith", no commas, semicolons, or other punctuation.

    [But will "Bob Smith" find "Smith, Bob"? (And presumably you still need quotes if sending to MLK, Jr.) -Raymond]
  33. Wow! All these comments make me think people really need to learn coding. It is absolutely compulsory for a lot of people here.

  34. Marc K says:

    @Fleet Command: "Interesting. :) Feedback by whom?"

    Someone with an expensive support contract.  

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