Complex sentence: This software was often bundled with free software which the user intentionally installed; since permission to install the 180solutions adware was typically hidden in an EULA, most users were unaware they were installing adware.
Split into simpler sentences: This software was often bundled with other pieces of free software which the user intentionally installed. Since permission to install the 180solutions adware was typically hidden in an EULA, most users were unaware they were installing adware.