How convert .all files to .csh files

CS4 is not able to import .all files. The last version of Cubase that could import .all files was Cubase SX3 (which is discontinued). A license of Cubase 7.5 can open SX3 as long as you have installed the latest eLCC from http://www.elicenser.net/en/latest_downloads.html and are on an OS that SX3 was supported for.