Q: i lost all email in mail and can no longer access wifi printer since security update 2016-003

Hello davidnaegele,

I understand you have lost all your emails in the Mail app as well as Wi-Fi printer access after updating to OS X 10.11.5. Updates are designed to improve your Mac so we can understand the concern it would cause when problems arise after updating. 

The first thing you will want to do is check to see if your email accounts are still set up. To do this, Open up Mail and select "Accounts" from the Apple menu bar. If you no longer see your email accounts listed, follow these steps to add your accounts back:

1. Select Add Account.
2. Select an account type.
3. Enter your account information and make sure the Mail checkbox is selected for the account. 

Mail (El Capitan): Set up Mail with your email accounts

If your email accounts are still set up in Mail > Accounts, follow the steps listed in this article:

Mail (El Capitan): If messages appear to be missing

For your printer connection issue, follow the troubleshooting steps in this article: Get help resolving printer issues on your Mac - Apple Support

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Have a great day.