--- a/src/AudacityApp.cpp
+++ b/src/AudacityApp.cpp
@@ -1640,7 +1640,7 @@ bool AudacityApp::CreateSingleInstanceCh
    mChecker = new wxSingleInstanceChecker();
 
 #if defined(__UNIX__)
-   wxString sockFile(defaultTempDir + wxT("/.audacity.sock"));
+   wxString sockFile(dir + wxT("/.audacity.sock"));
 #endif
 
    wxString runningTwoCopiesStr = _("Running two copies of Audacity simultaneously may cause\ndata loss or cause your system to crash.\n\n");