diff --git a/Services/RecipeGenerator.cs b/Services/RecipeGenerator.cs
--- a/Services/RecipeGenerator.cs
+++ b/Services/RecipeGenerator.cs
@@ -186,6 +186,12 @@ namespace DesertPaintCodex.Services
             FullQuantity = fullQuantity;
             FullQuantityDepth = fullQuantityDepth;
 
+            // Sanity check
+            if (MinConcentration < 10) MinConcentration = 10;
+            if (MaxConcentration < MinConcentration) MaxConcentration = MinConcentration;
+            if (MinReagents < 1) MinReagents = 1;
+            if (MaxReagents < MinReagents) MaxReagents = MinReagents;
+
             // first, sort reagents by cost.
             InitSortedReagents();
 
@@ -521,6 +527,12 @@ namespace DesertPaintCodex.Services
             if (!done) return;
             
             _running       = false;
+            if (!_requestCancel && !_searchQueue.IsEmpty)
+            {
+                Debug.WriteLine($"Recipe generation complete, but search queue isn't empty {_searchQueue.Count}.");
+                WriteLog($"Recipe generation complete, but search queue isn't empty {_searchQueue.Count}.");
+                _searchQueue.Clear();
+            }
             _requestCancel = false;
             Finished?.Invoke(this, EventArgs.Empty);
         }