diff --git a/.gitignore b/.gitignore
index e276a405f..7d00536a8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,6 +20,7 @@ docs/_build/
 docs/envvarsbody
 docs/xontribsbody
 xonsh/dev.githash
+**/__pycache__/
 
 # temporary files from vim and emacs
 *~
diff --git a/xonsh/commands_cache.py b/xonsh/commands_cache.py
index 2c954980e..6eb283d98 100644
--- a/xonsh/commands_cache.py
+++ b/xonsh/commands_cache.py
@@ -133,7 +133,10 @@ class CommandsCache(abc.Mapping):
                 if os.path.isfile(full_name)
             ), None)
             if local_bin:
-                return os.path.abspath(os.path.relpath(local_bin, cwd))
+                if os.path.splitdrive(cwd)[0] != os.path.splitdrive(local_bin)[0]:  # if cwd not on same drive as bin
+                    return os.path.abspath(local_bin)                               # avoid ValueError in relpath()
+                else:
+                    return os.path.abspath(os.path.relpath(local_bin, cwd))
 
         cached = next((cmd for cmd in possibilities if cmd in self._cmds_cache), None)
         if cached: