diff --git a/preferencesdialog.cpp b/preferencesdialog.cpp
index a37bf555..f6a0a2e4 100644
--- a/preferencesdialog.cpp
+++ b/preferencesdialog.cpp
@@ -305,8 +305,11 @@ bool PreferencesDialog::Save()
             needs_restart=true;
         else recalc_events=true;
     }
+
+    if (profile->session->compressSessionData()!=ui->compressSessionData->isChecked()) recalc_events=true;
+
     if (recalc_events) {
-        if (QMessageBox::question(this,tr("Data Reindex Required"),tr("A lengthy data reindexing proceedure is required to apply these changes.\n\nAre you sure you want to make these changes?"),QMessageBox::Yes,QMessageBox::No)==QMessageBox::No) {
+        if (QMessageBox::question(this,tr("Data Reindex Required"),tr("A data reindexing proceedure is required to apply these changes.\n\nAre you sure you want to make these changes?"),QMessageBox::Yes,QMessageBox::No)==QMessageBox::No) {
             return false;
         }
     } else if (needs_restart) {