diff --git a/README b/README
index f73b0f4..a10dfe1 100644
--- a/README
+++ b/README
@@ -56,10 +56,14 @@ isync executable still exists; it is a compatibility wrapper around mbsync.
 * Platforms
 
     At some point, ``isync'' has successfully run on:
-    Linux, Solaris 2.7, OpenBSD 2.8, FreeBSD 4.3, Cygwin
+    Linux, Solaris 2.7, OpenBSD 2.8, FreeBSD 4.3.
+
+    Note that Cygwin cannot be reasonably supported due to restrictions
+    of the Windows file system.
 
 * Requirements
 
+    Berkley DB 4.2+
     OpenSSL for TLS/SSL support (optional)
 
 * Installation