can't install software outside of the market??

[2719595]

I downloaded some software from some website...
But, how come my inspire can't install other software from outside of the market?
I make a lot of research..they all said there is a check box said "unknown source" in setting-application....however..I can't find it the "unknown source"..
Can anyone help??

 

[BigDaddyHicks]

AT&T blocks the installation of 3rd party apps. I have no idea if rooting will fix this for you but you CAN use the sideloader found here in the forums for installing 3rd party apps.

 

[Smitty_82]

All the information is here http://forum.androidcentral.com/android-sideload-wonder-machine/