diff --git a/nb_conda_kernels/manager.py b/nb_conda_kernels/manager.py
index 2be34f6..2bdb53e 100644
--- a/nb_conda_kernels/manager.py
+++ b/nb_conda_kernels/manager.py
@@ -6,6 +6,7 @@
 import sys
 import time
 import glob
+import psutil
 
 import os
 from os.path import join, split, dirname, basename, abspath
@@ -138,6 +139,8 @@ def _conda_info(self):
             self._conda_info_cache = conda_info
             self._conda_info_cache_expiry = time.time() + CACHE_TIMEOUT
 
+        self.wait_for_child_processes_cleanup()
+
         return self._conda_info_cache
 
     def _all_envs(self):
@@ -390,3 +393,11 @@ def remove_kernel_spec(self, name):
         else:
             shutil.rmtree(spec_dir)
         return spec_dir
+
+    def wait_for_child_processes_cleanup(self):
+        p = psutil.Process()
+        for c in p.children():
+            try:
+                c.wait(timeout=0)
+            except psutil.TimeoutExpired:
+                pass
diff --git a/requirements.txt b/requirements.txt
index 54dd2c7..1bfe6b3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,6 +3,7 @@ jupyter_client
 r-irkernel
 requests
 flake8
+psutil
 pytest
 pytest-cov
 mock
diff --git a/testbed/testenv1.yaml b/testbed/testenv1.yaml
index 62fea6b..da0c2ac 100644
--- a/testbed/testenv1.yaml
+++ b/testbed/testenv1.yaml
@@ -3,4 +3,4 @@ dependencies:
   - backports.functools_lru_cache
   - r-irkernel
   - conda-forge::ipykernel
-  - python=2
+  - python=3
diff --git a/tests/test_runner.py b/tests/test_runner.py
index c2b0036..2b92747 100644
--- a/tests/test_runner.py
+++ b/tests/test_runner.py
@@ -11,7 +11,6 @@
 
 from nb_conda_kernels.discovery import CondaKernelProvider
 from nb_conda_kernels.manager import RUNNER_COMMAND
-from jupyter_client.blocking.client import Empty
 
 START_TIMEOUT = 10
 CMD_TIMEOUT = 3