How to Make Outlook Allow Commas to Separate Multiple Email Recipients
To have Outlook see commas when separating multiple email recipients:
Why Comma Separators Don’t Work in Outlook
In most email programs, it’s common practice to separate the names of email recipients with commas. However, in Outlook, the semicolon is used to separate email recipients. If you’d rather use a comma, change the Outlook settings. If commas are used to separate recipients in Outlook, a “name could not be resolved” message will appear. This means that Outlook doesn’t understand the syntax used when typing the recipient addresses. Outlook interprets commas as separating the last name from a first name. For example, if you enter she@example.com, Mark, Outlook will read the recipient as Mark she@example.com.
How to Allow Commas to Separate Multiple Email Recipients in Outlook.com
Outlook.com automatically recognizes a comma between email addresses as the separator between contacts.