For a full list of articles about security, see Overview of security in Acrobat DC and PDFs.
Protected View provides an additional level of security. When Protected View is enabled, PDFs are displayed in a restricted environment called a sandbox. This isolation of the PDFs reduces the risk of security breaches in areas outside the sandbox. Adobe strongly recommends that you use Acrobat in Protected View if you are concerned about security, or if you frequently interact with PDFs on the Internet.
Adobe Reader includes a similar restricted environment called Protected Mode. For information about Reader Protected Mode, see Reader Help.
When Protected View is enabled, only basic navigation is allowed. For example, you can open PDFs, scroll through pages, and click links. You can enable Protected View in a PDF that you view in either stand-alone Acrobat or in a web browser.
PDF in stand-alone Acrobat
In Protected View, Acrobat displays a warning for a PDF that doesn’t originate from a trusted location. The warning lets you decide whether to trust the document.
You can find out whether a PDF opened in a browser is in Protected View. Right-click the document in the browser and choose Document Properties. Click the Advanced tab. When Protected View is enabled, the status says Protected Mode: On.
Select Off in the Enhanced Security panel of the Security (Enhanced) preferences.
Add files, folders, and locations to the Privileged Locations area of the Enhanced Security panel. (See Specify privileged locations for trusted content.)