diff --git a/src/PluginManager.cpp b/src/PluginManager.cpp
index 2b2050f7a..20c1c5120 100644
--- a/src/PluginManager.cpp
+++ b/src/PluginManager.cpp
@@ -1770,6 +1770,40 @@ void PluginManager::Load()
 
 void PluginManager::LoadGroup(wxFileConfig *pRegistry, PluginType type)
 {
+#ifdef __WXMAC__
+   // Bug 1590: On Mac, we should purge the registry of Nyquist plug-ins
+   // bundled with other versions of Audacity, assuming both versions
+   // were properly installed in /Applications (or whatever it is called in
+   // your locale)
+
+   const auto fullExePath = PlatformCompatibility::GetExecutablePath();
+
+   // Strip rightmost path components up to *.app
+   wxFileName exeFn{ fullExePath };
+   exeFn.SetEmptyExt();
+   exeFn.SetName(wxString{});
+   while(exeFn.GetDirCount() && !exeFn.GetDirs().Last().EndsWith(".app"))
+      exeFn.RemoveLastDir();
+
+   const auto goodPath = exeFn.GetPath();
+
+   if(exeFn.GetDirCount())
+      exeFn.RemoveLastDir();
+   const auto possiblyBadPath = exeFn.GetPath();
+
+   auto AcceptPath = [&](const wxString &path) {
+      if (!path.StartsWith(possiblyBadPath))
+         // Assume it's not under /Applications
+         return true;
+      if (path.StartsWith(goodPath))
+         // It's bundled with this executable
+         return true;
+      return false;
+   };
+#else
+   auto AcceptPath = [](const wxString&){ return true; };
+#endif
+
    wxString strVal;
    bool boolVal;
    wxString groupName;
@@ -1814,6 +1848,11 @@ void PluginManager::LoadGroup(wxFileConfig *pRegistry, PluginType type)
 
       // Get the path (optional)
       pRegistry->Read(KEY_PATH, &strVal, wxEmptyString);
+      if (!AcceptPath(strVal))
+         // Ignore the obsolete path in the config file, during session,
+         // but don't remove it from the file.  Maybe you really want to
+         // switch back to the other version of Audacity and lose nothing.
+         continue;
       plug.SetPath(strVal);
 
       // Get the name and bypass group if not found