diff --git a/lib/spack/spack/detection/common.py b/lib/spack/spack/detection/common.py
index 8cb9d7d3acf..3e9856766fa 100644
--- a/lib/spack/spack/detection/common.py
+++ b/lib/spack/spack/detection/common.py
@@ -218,8 +218,10 @@ def update_configuration(detected_packages, scope=None, buildable=True):
 
 
 def _windows_drive():
-    """Return Windows drive string"""
-    return os.environ["HOMEDRIVE"]
+    """Return Windows drive string extracted from PROGRAMFILES
+    env var, which is garunteed to be defined for all logins"""
+    drive = re.match(r"([a-zA-Z]:)", os.environ["PROGRAMFILES"]).group(1)
+    return drive
 
 
 class WindowsCompilerExternalPaths(object):