diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc
index c8e73c64c..a00270210 100644
--- a/winsup/cygwin/path.cc
+++ b/winsup/cygwin/path.cc
@@ -1411,7 +1411,7 @@ normalize_win32_path (const char *src, char *dst, char *&tail)
       && src[2] == '?' && isdirsep (src[3]))
     {
       src += 4;
-      if (isdrive (src) && isdirsep (src[2]))
+      if (isdrive (src) && (isdirsep (src[2]) || !src[2]))
 	beg_src_slash = false;
       else if (!strncmp (src, "UNC", 3) && isdirsep (src[3]))
 	/* native UNC path */
diff --git a/winsup/cygwin/release/3.1.3 b/winsup/cygwin/release/3.1.3
index 0fcdccabb..489741136 100644
--- a/winsup/cygwin/release/3.1.3
+++ b/winsup/cygwin/release/3.1.3
@@ -6,3 +6,7 @@ Bug Fixes
 
 - Fix the problem which overrides the code page setting.
   Addresses: https://www.cygwin.com/ml/cygwin/2019-12/msg00292.html
+
+- Fix a regression that prevents the root of a drive from being the
+  Cygwin installation root.
+  Addresses: https://cygwin.com/ml/cygwin/2020-01/msg00111.html