                      :truncate-lines helm-grep-truncate-lines))
              (cl-return t))
             (`ag
-             (list "ag -zS --nocolor --nogroup"
+             (list "ag -zS"
+                   (if IS-WINDOWS "--vimgrep" "--nocolor --nogroup")
                    (when all-files "-a")
                    (unless recursive "--depth 1")))
             (`rg

                               (if recursive " -R" "")
                               (if recursive "." "./*"))))
                    (helm-grep-default-recurse-command helm-grep-default-command))
               (message "-- %s (%s)" helm-grep-default-command query)
               (setq helm-source-grep
                     (helm-build-async-source (capitalize (helm-grep-command t))
                       :header-name (lambda (_name) "Helm Projectile Grep (C-c ? Help)")

         (directory (or in project-root))
         (default-directory directory)
         (helm-ag--default-directory directory)
         (helm-ag--default-target (list directory))
         (engine (or engine
                     (and (executable-find "rg") 'rg)
                     (and (executable-find "ag") 'ag)
