diff --git a/AllenOnline/src/MEPProvider.cpp b/AllenOnline/src/MEPProvider.cpp
index bc9eeb56229d97a41725fd52d5dcadc4e51d738e..c814974da5a10ce2e9fe874dbfde5bae11bf9036 100755
--- a/AllenOnline/src/MEPProvider.cpp
+++ b/AllenOnline/src/MEPProvider.cpp
@@ -116,7 +116,7 @@ std::tuple<bool, bool, bool, size_t, size_t, std::any> MEPProvider::get_slice( s
   if ( !m_read_error ) {
     // If no transposed slices are ready for processing, wait until
     // one is; use a timeout if requested
-    if ( m_transposed.empty() ) {
+    if ( !has_transposed() ) {
       auto wakeup = [this, &has_transposed] { return ( has_transposed() || m_read_error || m_transpose_done ); };
       if ( timeout ) {
         timed_out = !m_transposed_cond.wait_for( lock, std::chrono::milliseconds{*timeout}, wakeup );