Unicode version consums 2 bytes per char. It means you need about 700MB for your file. Each process in Windows is limited by 2GB of memory independent of your fyzical memory.
Highlighting is stoped by parameter: Program settings / Direct edit HlUpToSize=nnn (size in bytes) You can increase value of this variable or manually switch on highlighting by toolbutton or menu item in the menu View -- <http://forum.pspad.com/read.php?2,33265,41152> PSPad freeware editor http://www.pspad.com
