diff --git a/news/4273.bugfix.rst b/news/4273.bugfix.rst
new file mode 100644
index 00000000..a6140178
--- /dev/null
+++ b/news/4273.bugfix.rst
@@ -0,0 +1 @@
+Fix a bug that Pipenv rejects to work under the root directory.
diff --git a/pipenv/core.py b/pipenv/core.py
index 1938e7f5..a90afa60 100644
--- a/pipenv/core.py
+++ b/pipenv/core.py
@@ -126,8 +126,11 @@ def do_clear():
 
     try:
         vistir.path.rmtree(PIPENV_CACHE_DIR, onerror=vistir.path.handle_remove_readonly)
+        # Other processes may be writing into this directory simultaneously.
         vistir.path.rmtree(
-            locations.USER_CACHE_DIR, onerror=vistir.path.handle_remove_readonly
+            locations.USER_CACHE_DIR,
+            ignore_errors=environments.PIPENV_IS_CI,
+            onerror=vistir.path.handle_remove_readonly
         )
     except OSError as e:
         # Ignore FileNotFoundError. This is needed for Python 2.7.
@@ -568,14 +571,6 @@ def ensure_project(
         system = True
     if not project.pipfile_exists and deploy:
         raise exceptions.PipfileNotFound
-    # Fail if working under /
-    if not project.name:
-        click.echo(
-            "{0}: Pipenv is not intended to work under the root directory, "
-            "please choose another path.".format(crayons.red("ERROR")),
-            err=True
-        )
-        sys.exit(1)
     # Skip virtualenv creation when --system was used.
     if not system:
         ensure_virtualenv(
diff --git a/pipenv/project.py b/pipenv/project.py
index 16bc715d..796489f7 100644
--- a/pipenv/project.py
+++ b/pipenv/project.py
@@ -682,18 +682,10 @@ class Project(object):
 
     def create_pipfile(self, python=None):
         """Creates the Pipfile, filled with juicy defaults."""
-        from .vendor.pip_shims.shims import (
-            ConfigOptionParser, make_option_group, index_group
-        )
-
-        config_parser = ConfigOptionParser(name=self.name)
-        config_parser.add_option_group(make_option_group(index_group, config_parser))
-        install = config_parser.option_groups[0]
-        indexes = (
-            " ".join(install.get_option("--extra-index-url").default)
-            .lstrip("\n")
-            .split("\n")
-        )
+        from .vendor.pip_shims.shims import InstallCommand
+        # Inherit the pip's index configuration of install command.
+        command = InstallCommand()
+        indexes = command.cmd_opts.get_option("--extra-index-url").default
         sources = [DEFAULT_SOURCE]
         for i, index in enumerate(indexes):
             if not index: