Characters in passwords or user names in Office 365

Written by: Chris deMaagd

What characters can I use when creating a password or user name in Office 365? What characters should I avoid?

List of characters

The following table lists all of the characters that you can and cannot use in a password or user name in Office 365.

Character name	Character	OK to use in password?	OK to use in user name?
Accent	`	Yes	No
Ampersand	&	Yes	No
Angle brackets	< >	Yes	No
Apostropher	'	Yes	No
Asterisk	*	Yes	No
At symbol	@	Yes	No
Backslash	\	Yes	No
Braces	[ ]	Yes	No
Brackets	{ }	Yes	No
Circumflex	^	Yes	No
Colon	:	Yes	No
Comma	,	Yes	No
Dollar sign	$	Yes	No
Equal sign	=	Yes	No
Exclamation point	!	Yes	No
Hyphen (a/k/a "minus sign")	-	Yes	No
Number sign	#	Yes	No
Parentheses	( )	Yes	No
Percent sign	%	Yes	No
Period	.	Yes	Yes*
Pipe	\|	Yes	No
Plus sign	+	Yes	No
Question mark	?	Yes	No
Quotation marks	"	Yes	No
Semicolon	;	Yes	No
Slash mark (a/k/a "forward slash")	/	Yes	No
Tilde	~	Yes	No
Underscore	_	Yes	Yes**
Uppercase letters	A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z	Yes	Yes
Lowercase letters	a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z	Yes	Yes
Numerals	0, 1, 2, 3, 4, 5, 6, 7, 8, 9	Yes	Yes

* You can put a period anywhere in your user name except at the very beginning or at the very end.
** You can put an underscore anywhere in your user name, including at the very beginning or at the very end.

Why can't I use some characters in my user name?

The reason you can’t use some characters in your user name has to do with the programming language that comprises Office 365, called C# (a/k/a "C sharp"). C#, like any other programming language, utilizes not just words or phrases, such as go to or find all; it also relies on many characters that compose the commands that tell Office 365 what to do.

For example, in C#, the dollar sign character ($) doesn't imply money; rather, it's a command that instructs Office 365 to treat the word or set of characters that precedes the dollar sign character as yet another command. So, in C#, the phrase Valx$ would mean, in computer-ese, "when you see the letters V-a-l-x in that order, you are to use it to…" The reason, then, that you can't use $ in your user name is because you don't want Office 365 to inadvertently treat any part of your password as an actionable "phrase" of C#. It's the same with the rest of the characters that you can’t use in a password or user name, each of which has a specific function in C#.

Is there anything else I can't use?

Other things that you can't use in a password or user name include the following:

Line breaks
Spaces
Tabs
>Unicode characters (for more information about Unicode, see the Unicode website)
In Office 365 for professionals and small businesses, any of your last ten passwords—though you may use any letters or characters that you've used in the past

In a password, you can't use your user name (that is, the entire part of your Office 365 ID that precedes the @ symbol).

For more information about passwords and user names, see the following Help articles:

For Office 365 for professionals and small businesses, see Change your password, Sign in to Office 365, and Reset a user's password
For Office 365 for enterprises, see Change your password, Sign in to Office 365, and Reset a user's password

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Comments

- Justin Barker
- 2011-Aug-23 3:59 PM
Great article, but one small contradiction. You list $ is available for use as a password character but then in the text you say it can't. Might need clearing up, but a great reference nonetheless
- Chris_MSFT
- 2011-Sep-22 11:41 AM
Justin,

Thanks for your eagle eye! We've corrected the error.
- Ryano
- 2011-Dec-28 6:25 PM
Chris, thanks for the insight into C# and the use of special characters. I'm not intimately familiar with the C# language, and I'm afraid I already know the answer, but is there any workaround for adding a connected account to Outlook which includes a special character? In this instance, the email address I use on one exchange server includes the apostrophe in my last name, Ryan.O'Connor@email.com. I had hoped to connect to that server using Outlook in Office 365, but I'm unable to. As I stated earlier, I'm hoping there may be some workaround available to allow me access to this account online.