If you haven't tried using the new authentication method, Java Web Start, to access the USPTO PAIR and EFS systems, the following primer (Macintosh computer running Mac OS X (El Capitan) 10.11.6, updated Safari and Firefox web browsers) should help. Please note that using the Java Web Start method still requires having Java installed on your computer.
Sept 9, 2017 Update. Option A does not work with Mac OS Sierra, but Option B still works.
1. On the USPTO website, you will have these options.
2. Select the "Authenticate with Java Web Start (new method)".
3. You will be greeted by this message
4. In the background, a file will have downloaded to your "Downloads" folder.
5. Depending on the security settings on your Macintosh, it may not run automatically. If you run the file and get the following error message:
Then, the following steps should allow it to run.
OPTION A - SLOWER METHOD 6A. Go to your "System Preferences" --> "Security & Privacy" Pane. 7A. Give permission for the application to run by clicking "Open Anyway".
8A. You will get the following message, click "Open".
9A. Java should run, and another pop-up message will appear. Click "Run".
10A. Another pop-up window should appear. After you enter your sign-in information, click "Authenticate".
11A. The window should close. You should be returned to your web browser, and you should be logged into the appropriate USPTO system. OPTION B - FASTER METHOD 6B. Press Control key and Right click Open the file. 7B. Java should run, and another pop-up message will appear. Click "Run".
8B. Another pop-up window should appear. After you enter your sign-in information, click "Authenticate".
9B. The window should close. You should be returned to your web browser, and you should be logged into the appropriate USPTO system. Hats off to Robert Rose for reminding me about the faster option.