diff --git a/Aaru.Gui/ViewModels/Windows/ImageEntropyViewModel.cs b/Aaru.Gui/ViewModels/Windows/ImageEntropyViewModel.cs
index 885fb923b..e46dfac24 100644
--- a/Aaru.Gui/ViewModels/Windows/ImageEntropyViewModel.cs
+++ b/Aaru.Gui/ViewModels/Windows/ImageEntropyViewModel.cs
@@ -301,6 +301,14 @@ namespace Aaru.Gui.ViewModels.Windows
             StopVisible                            =  false;
             ProgressVisible                        =  true;
 
+            if(WholeDiscChecked                                 &&
+               _inputFormat is IOpticalMediaImage opticalFormat &&
+               opticalFormat.Sessions?.Count > 1)
+            {
+                AaruConsole.ErrorWriteLine("Calculating disc entropy of multisession images is not yet implemented.");
+                WholeDiscChecked = false;
+            }
+
             var thread = new Thread(async () =>
             {
                 if(SeparatedTracksChecked)
@@ -315,7 +323,7 @@ namespace Aaru.Gui.ViewModels.Windows
                         if(trackEntropy.UniqueSectors != null)
                             AaruConsole.WriteLine("Track {0} has {1} unique sectors ({2:P3})", trackEntropy.Track,
                                                   trackEntropy.UniqueSectors,
-                                                  (double)trackEntropy.UniqueSectors / (double)trackEntropy.Sectors);
+                                                  (double)trackEntropy.UniqueSectors / trackEntropy.Sectors);
                     }
                 }
 
@@ -347,7 +355,7 @@ namespace Aaru.Gui.ViewModels.Windows
                         Track = trackEntropy.Track.ToString(),
                         Entropy = trackEntropy.Entropy.ToString(CultureInfo.CurrentUICulture),
                         UniqueSectors =
-                            $"{trackEntropy.UniqueSectors} ({(double)(trackEntropy.UniqueSectors ?? 0) / (double)trackEntropy.Sectors:P3})"
+                            $"{trackEntropy.UniqueSectors} ({(trackEntropy.UniqueSectors ?? 0) / (double)trackEntropy.Sectors:P3})"
                     });
             }
 
@@ -361,7 +369,7 @@ namespace Aaru.Gui.ViewModels.Windows
                 return;
 
             MediaUniqueSectorsText =
-                $"Disk has {_entropy.UniqueSectors} unique sectors ({(double)_entropy.UniqueSectors / (double)_entropy.Sectors:P3})";
+                $"Disk has {_entropy.UniqueSectors} unique sectors ({(double)_entropy.UniqueSectors / _entropy.Sectors:P3})";
 
             MediaUniqueSectorsVisible = true;
         }
diff --git a/Aaru/Commands/Image/Entropy.cs b/Aaru/Commands/Image/Entropy.cs
index 36a4b60b3..60dea6483 100644
--- a/Aaru/Commands/Image/Entropy.cs
+++ b/Aaru/Commands/Image/Entropy.cs
@@ -133,6 +133,14 @@ namespace Aaru.Commands.Image
             entropyCalculator.EndProgressEvent     += Progress.EndProgress;
             entropyCalculator.EndProgress2Event    += Progress.EndProgress2;
 
+            if(wholeDisc                                       &&
+               inputFormat is IOpticalMediaImage opticalFormat &&
+               opticalFormat.Sessions?.Count > 1)
+            {
+                AaruConsole.ErrorWriteLine("Calculating disc entropy of multisession images is not yet implemented.");
+                wholeDisc = false;
+            }
+
             if(separatedTracks)
             {
                 EntropyResults[] tracksEntropy = entropyCalculator.CalculateTracksEntropy(duplicatedSectors);
@@ -144,7 +152,7 @@ namespace Aaru.Commands.Image
                     if(trackEntropy.UniqueSectors != null)
                         AaruConsole.WriteLine("Track {0} has {1} unique sectors ({2:P3})", trackEntropy.Track,
                                               trackEntropy.UniqueSectors,
-                                              (double)trackEntropy.UniqueSectors / (double)trackEntropy.Sectors);
+                                              (double)trackEntropy.UniqueSectors / trackEntropy.Sectors);
                 }
             }
 
@@ -157,7 +165,7 @@ namespace Aaru.Commands.Image
 
             if(entropy.UniqueSectors != null)
                 AaruConsole.WriteLine("Disk has {0} unique sectors ({1:P3})", entropy.UniqueSectors,
-                                      (double)entropy.UniqueSectors / (double)entropy.Sectors);
+                                      (double)entropy.UniqueSectors / entropy.Sectors);
 
             return (int)ErrorNumber.NoError;
         }