diff --git a/HISTORY.txt b/HISTORY.txt
index 0e4cf48d..abc03e3c 100644
--- a/HISTORY.txt
+++ b/HISTORY.txt
@@ -9,6 +9,7 @@
     (thanks @hroncok @uranusjr and @ncoghlan for your help sorting this out).
  - Remove GPL'ed code.
  - Make imports lazy to improve initial load time.
+ - Extra path searching for python at runtime.
  - Require `--python` values to exist when passing a path.
  - Bugfix for environment variable expansion in 'unlocked' pipfiles.
  - Bugfix for `--deploy` flag.
diff --git a/pipenv/__version__.py b/pipenv/__version__.py
index 851438ce..6b0d1446 100644
--- a/pipenv/__version__.py
+++ b/pipenv/__version__.py
@@ -2,4 +2,4 @@
 #   //   ) ) / / //   ) ) //___) ) //   ) ) ||  / /
 #  //___/ / / / //___/ / //       //   / /  || / /
 # //       / / //       ((____   //   / /   ||/ /
-__version__ = '11.10.1.dev4'
+__version__ = '11.10.1.dev5'
diff --git a/pipenv/core.py b/pipenv/core.py
index 31538033..1543983d 100644
--- a/pipenv/core.py
+++ b/pipenv/core.py
@@ -115,7 +115,7 @@ if PIPENV_NOSPIN:
 
 
 def which(command, location=None, allow_global=False):
-    if location is None:
+    if not allow_global and location is None:
         location = project.virtualenv_location or os.environ.get('VIRTUAL_ENV')
     if not allow_global:
         if os.name == 'nt':
@@ -127,6 +127,11 @@ def which(command, location=None, allow_global=False):
     else:
         if command == 'python':
             p = sys.executable
+    if not os.path.exists(p):
+        if command == 'python':
+            p = sys.executable or system_which('python')
+        else:
+            p = system_which(command)
     return p
 
 
@@ -1316,6 +1321,20 @@ def do_init(
                 )
                 requirements_dir.cleanup()
                 sys.exit(1)
+            elif system or allow_global:
+                click.echo(
+                    crayons.red(
+                        u'Pipfile.lock ({0}) out of date, but installation '
+                        u'uses {1}... re-building lockfile must happen in '
+                        u'isolation. Please rebuild lockfile in a virtualenv. '
+                        u'Continuing anyway...'.format(
+                            crayons.white(old_hash[-6:]),
+                            crayons.white('--system')
+                        ),
+                        bold=True,
+                    ),
+                    err=True,
+                )
             else:
                 click.echo(
                     crayons.red(
@@ -1329,16 +1348,28 @@ def do_init(
                 do_lock(system=system, pre=pre, keep_outdated=keep_outdated)
     # Write out the lockfile if it doesn't exist.
     if not project.lockfile_exists and not skip_lock:
-        click.echo(
-            crayons.normal(u'Pipfile.lock not found, creating…', bold=True),
-            err=True,
-        )
-        do_lock(
-            system=system,
-            pre=pre,
-            keep_outdated=keep_outdated,
-            verbose=verbose,
-        )
+        if system or allow_global:
+            click.echo(
+                '{0}: --system is intended to be used for Pipfile installation, '
+                'not installation of specific packages. Aborting.'.format(
+                    crayons.red('Warning', bold=True)
+                ),
+                err=True,
+            )
+            click.echo('See also: --deploy flag.', err=True)
+            requirements_dir.cleanup()
+            sys.exit(1)
+        else:
+            click.echo(
+                crayons.normal(u'Pipfile.lock not found, creating…', bold=True),
+                err=True,
+            )
+            do_lock(
+                system=system,
+                pre=pre,
+                keep_outdated=keep_outdated,
+                verbose=verbose,
+            )
     do_install_dependencies(
         dev=dev,
         requirements=requirements,
diff --git a/pipenv/utils.py b/pipenv/utils.py
index 78b85f1e..10e3ae75 100644
--- a/pipenv/utils.py
+++ b/pipenv/utils.py
@@ -405,7 +405,7 @@ def venv_resolve_deps(
 
     resolver = escape_grouped_arguments(resolver.__file__.rstrip('co'))
     cmd = '{0} {1} {2} {3} {4} {5}'.format(
-        escape_grouped_arguments(which('python')),
+        escape_grouped_arguments(which('python', allow_global=allow_global)),
         resolver,
         '--pre' if pre else '',
         '--verbose' if verbose else '',