From a little time, I have this problem.
Some messages are with strange characters.
Here an example, but sometimes a messages contains a lot of characters like that.
The word is HCI and then there is a S with an accent !!!
Why does this happen?
This is a text encoding problem that occurs when the sending email server is converting a message to send to another mail server. And it only affects plain text messages not HMTL formatted messages.
Not all service providers use the same mail server software and not all software plays nicely with each other. Therefore, an outgoing mail server (aka SMTP server) must convert an email message to a common format before relaying to the recipient’s email server. Generally, it’ll rely on the sending email application to tell it the best format.
Some servers such as Exchange (including Office 365) may decide the text encoding if it doesn’t recognize the one specified by the email application but it doesn’t always decide correctly. The recipient then sees strange characters in the message. Curly quotes may change to numbers and ellipses may change to accented characters.
Note the same issue appears not just in Outlook for Mac but other applications such as Mail for iPhone.
Under the hood
Microsoft Exchange servers are prevalent in the business world and are the platform behind Office 365. Therefore, they’re commonly involved in these text encoding issues.
As part of the conversion proccess the Exchange server includes a “Content-Type” header in the mail message to describe the encoding it used. To view this header in Outlook for Mac just right-click or Control-click a message and choose View Source. This opens the message in the Mac’s default plain text editor (usually TextEdit). Search for “Content-Type”.
Note the character set (charset) the server used is “Windows-1252”. This is probably fine for Windows computers but not helpful for Macs and other non-Windows devices receiving messages sent through Exchange.
Outlook for Mac tries to automatically detect the correct format of outgoing plain text emails and generally sends as Unicode (UTF-8), which should preserve characters such as curly quotes and ellipses. However, Exchange doesn’t seem to recognize or respect the text encoding as Outlook sends it (two lines with the second line preceded by a tab):
and uses “Windows-1252”.
Forcing Unicode (UTF-8)
To remedy this problem in Outlook for Mac, the sender can choose Format > Text Encoding > Unicode (UTF-8) before sending his message:
and the message will display correctly for the recipient.
With the Microsoft Office for Mac 2011 14.2.4 Update released in September 2012, Microsoft included a preference to set the default text encoding for all outgoing messages. However, it’s not enabled by default.
Choose Outlook > Preferences > Composing and select Preferred Encoding For New Messages: Unicode (UTF-8). All new plain text messages sent through Exchange servers or Office 365 should appear with the correct characters to the recipients.
Turn off Apple’s Substitutions
Optionally, if this preference interferes with other language settings consider disabling Apple’s Substitutions feature, which replaces text such as straight quotes with curly quotes and three periods with an ellipsis character. Disabling Outlook’s AutoCorrect feature does not disable Substitutions.
Choose Edit > Substitutions > Show Substitutions. Disable Smart Dashes to turn off not only converting double dashes to em dashes but also converting three periods to an ellipsis. Disable Smart Quotes to turn off converting straight quotes to curly quotes.