diff --git a/pcbnew/kicad_plugin.cpp b/pcbnew/kicad_plugin.cpp
index d4868db5b3..87d1428c0e 100644
--- a/pcbnew/kicad_plugin.cpp
+++ b/pcbnew/kicad_plugin.cpp
@@ -372,6 +372,16 @@ bool FP_CACHE::IsModified( const wxString& aLibPath, const wxString& aFootprintN
     if( !m_lib_path.DirExists() || !IsPath( aLibPath ) )
         return true;
 
+    wxLogTrace( traceFootprintLibrary, wxT( "File '%s', m_mod_time %s-%s, file mod time: %s-%s." ),
+                GetChars( m_lib_path.GetPath() ),
+                GetChars( m_mod_time.FormatDate() ), GetChars( m_mod_time.FormatTime() ),
+                GetChars( m_lib_path.GetModificationTime().FormatDate() ),
+                GetChars( m_lib_path.GetModificationTime().FormatTime() ) );
+
+    // If a file is added to or remove from the library path, the cache needs reloaded.
+    if( m_mod_time != m_lib_path.GetModificationTime() )
+        return true;
+
     // If no footprint was specified, check every file modification time against the time
     // it was loaded.
     if( aFootprintName.IsEmpty() )