diff --git a/BFR/Operations/Replace.cs b/BFR/Operations/Replace.cs
index 35b62ff..d57a6c9 100644
--- a/BFR/Operations/Replace.cs
+++ b/BFR/Operations/Replace.cs
@@ -38,14 +38,14 @@ namespace BFR.Operations
         {
             // Fail conditions: Various out-of-bounds
             var shortestLength = files.Min(x => FullName ? x.FullName.Length : x.Name.Length);
-            if (FirstN > shortestLength) throw new OperationException($"First N can't be greater than the shortest file name length ({shortestLength}).");
-            if (LastN > shortestLength) throw new OperationException($"Last N can't be greater than the shortest file name length ({shortestLength}).");
-            if (FromN > shortestLength) throw new OperationException($"From N can't be greater than the shortest file name length ({shortestLength}).");
-            if (ToN > shortestLength) throw new OperationException($"To N can't be greater than the shortest file name length ({shortestLength}).");
-            if (FromN > ToN) throw new OperationException("From N can't be greater than To N.");
+            if (Mode == ReplaceMode.FirstN && FirstN > shortestLength) throw new OperationException($"First N can't be greater than the shortest file name length ({shortestLength}).");
+            if (Mode == ReplaceMode.LastN && LastN > shortestLength) throw new OperationException($"Last N can't be greater than the shortest file name length ({shortestLength}).");
+            if (Mode == ReplaceMode.FromNToN && FromN > shortestLength) throw new OperationException($"From N can't be greater than the shortest file name length ({shortestLength}).");
+            if (Mode == ReplaceMode.FromNToN && ToN > shortestLength) throw new OperationException($"To N can't be greater than the shortest file name length ({shortestLength}).");
+            if (Mode == ReplaceMode.FromNToN && FromN > ToN) throw new OperationException("From N can't be greater than To N.");
 
             // Regex Failure
-            if(Modes[(int)Mode].IsPattern && UseRegex)
+            if(Mode == ReplaceMode.Pattern && UseRegex)
                 try { "".Replace(Pattern, Replacement, true, false); }
                 catch(Exception) { throw new OperationException("Invalid Regex Pattern."); }