diff --git a/src/effects/nyquist/Nyquist.cpp b/src/effects/nyquist/Nyquist.cpp
index ff3607504..b78157608 100644
--- a/src/effects/nyquist/Nyquist.cpp
+++ b/src/effects/nyquist/Nyquist.cpp
@@ -539,7 +539,7 @@ bool NyquistEffect::Process()
       mProps += wxString::Format(wxT("(putprop '*SYSTEM-TIME* \"%s\" 'DAY-NAME)\n"), now.GetWeekDayName(day).c_str());
 
       // TODO: Document: Number of open projects
-      mProps += wxString::Format(wxT("(putprop '*PROJECT* %d 'PROJECTS)\n"), gAudacityProjects.size());
+      mProps += wxString::Format(wxT("(putprop '*PROJECT* %d 'PROJECTS)\n"), (int) gAudacityProjects.size());
       // TODO: Document. NOTE: unnamed project returns an empty string.
       mProps += wxString::Format(wxT("(putprop '*PROJECT* \"%s\" 'NAME)\n"), project->GetName().c_str());