"An error occurred while applying security settings. User is not a valid user or group."
On some operating systems (mainly non-English) the Mail Mining installer is not able to find the Users group.
To complete the installation a Users group must be created.
This can be done from Control Panel>Administrative Tools>Computer Management and then expanding System Tools>Local Users and Groups>Groups. Right click Groups and choose New Group, name it "Users". After adding the Users group, you should be able to complete the installation successfully.
System Requirements:
Windows 7, XP or Vista
Microsoft Outlook 2007