You can turn this mode off using a registry edit as below:
Registry Editing Method
Open notepad and paste the following command, when pasted save as a .reg file.
REG ADD "HKCU\SOFTWARE\Adobe\Acrobat Reader\10.0\Privileged" /v bProtectedMode /t REG_DWORD /d 0 /f
If using Server 2008R2 you can set a preference to make a change to the registry for users as below
Open Group Policy Management from Start > Administrative Tools > Group Policy Management
Create a new Group Policy Object
Give the GPO a suitable name
Right click and select edit
Expand the User Preferences menu option
Expand the Windows Settings and select Registry
In the blank area in the right hand pane right click and select New > Registry Item
Ensure that the settings are to ‘Update’ the registry key, also check that the selected hive is HKEY_CURRENT_USER.
In the Key path enter ‘SOFTWARE\Adobe\Acrobat Reader\10.0\Privileged’
Enter ‘bProtectedMode’ into the Value box
Change the value type to REG_DWORD
In the value box enter ‘0’
Click OK and you are done.
This is how the finished registry entry should look.