Microsoft Usage and Description README File Create File Tool (Creatfil.exe) July 16, 1993. 1. Description Create file tool (Creatfil.exe) is used to create a new file with the specified filename and file size. If the file is already existed, it will be deleted and replaced with a new file. If the specified file size is greater than the available space on the current drive, CreatFil will create a file up to the last 1K bytes and report a "Write file" error. 2. Usage CreatFil filename filesize filename -- name of the new file filesize -- size of the new file in KBytes. default is 1024 KBytes.