If you don’t know it yet, the best e-mail client for Windows is The Bat! (I wish they had it for Mac OS).

And if your company uses Office 365, then you can add your corporate e-mail account to The Bat! as well, because it is accessible via regular IMAP and SMTP, so you don’t have to deal with this horrible Outlook shit.

Here are the main settings for setting your Office 365 account in The Bat! (I tested it with version 7.4.16):

IMAP server: outlook.office365.com 
Connection: Secure to dedicated port (TLS) 
Port: 993

SMTP server: outlook.office365.com 
Connection: Secure to regular port (STARTTLS) 
Port: 587

When you will be creating your account in The Bat! leave Protocol type dropdown as Auto (or pick IMAP or POP). Then enter the servers and ports info. After you’ll finish this, open properties of your just created account and check the following screenshots:

The Bat Transport settings

In the User field you should enter the full e-mail address including domain. By default it sets only the part before @ symbol.

Here are the settings for IMAP authentication:

The Bat IMAP authentication

and SMTP authentication:

The Bat SMTP authentication

You might also want to add some non-default folders - it is done via Manage IMAP foldersmenu:

The Bat Manage IMAP folders

It’s done.

P.S. At some point The Bat! added EWS and MAPI support, so you can even use it with your internal Exchange server, but last time I tried it, it didn’t work for me (well, because I didn’t know the address of our internal server).