Leia a variável de ambiente PATHEXT artigo:
PathExt
environment variable returns a list of the file extensions that the operating system considers to be executable. When executing a command line that does not contain an extension, the command interpreter (cmd.exe
) uses the value of this environment variable to determine which extensions to look for and in what order.
Para restaurar variável (s) quebrada (s), leia e siga Como definir o caminho e as variáveis de ambiente no Windows