In the past (say, with Snow Leopard, although I don't remember exactly when I set up my old client) it used to be possible to have a "one-way synchronization" between the Mail client and a gmail account in the following sense: the Mail client would download any new messages that were sent to my email, but would not notify gmail of any changes that I made locally.
The main advantage of this setup is that I could have an unofficial "cloud storage": my local client would be where I actually did my work. It would contain the emails I actually needed to respond to, and my drafts, etc. But I could recklessly delete things locally with the knowledge that if I ever really needed them, even years later, I just had to log into my account online.
Is there any way to do this with El Capitan? or at least to simulate the effect somehow?
Best Answer
You are describing an account set up with POP3. To achieve that behavior follow this instructions:
First, set up POP in Gmail
Incoming Mail (POP) Server: pop.gmail.com
Requires SSL: Yes
Port: 995
Outgoing Mail (SMTP) Server: smtp.gmail.com
Requires SSL: Yes
Requires TLS: Yes (if available)
Requires Authentication: Yes
Port for SSL: 465
Port for TLS/STARTTLS: 587
If you use Gmail with your work or school account, enter mail.domain.com, then select Port 110.
Server timeouts Greater than 1 minute (5 is recommended)
Full Name or Display Name Your name
Account Name, User Name, or Email address Your email address
Password Your Gmail password
When adding your account choose "Other" instead of "Gmail" on Mail app.