I work with Acrobat Pro XI and need to restrict permissions to certain users of my pdf. Everyone can be allowed to open the form (no password required) but only certain people can edit, add comments etc. Unfortunately my 'permissions' facility under >tools >encrypt doesn't appear to be working - I can tick the boxes but no luck! Any help would be greatly appreciated.
When secure your PDF you leave the Open password unchecked and enter only Permissions password. You can do that only in full Acrobat (Standard/Pro). You cannot secure PDF in a free Reader. Keep in mind the alert that comes up when you do that: "All Adobe products enforce these permissions but 3rd party PDF Viewers may not", and many (like Mac Preview, many browsers' PDF Viewers, etc.) do not. So, this is not actually a reliable way to achieve what you want. If you want really fool-proof solution you need to employ a DRM like Adobe LiveCycle, but that costs money.