diff --git a/DiscImageChef.DiscImages/CDRDAO.cs b/DiscImageChef.DiscImages/CDRDAO.cs
index 6f513ad6..305de8fd 100644
--- a/DiscImageChef.DiscImages/CDRDAO.cs
+++ b/DiscImageChef.DiscImages/CDRDAO.cs
@@ -248,9 +248,22 @@ namespace DiscImageChef.ImagePlugins
 				imageFilter.GetDataForkStream().Read(testArray, 0, 512);
 				imageFilter.GetDataForkStream().Seek(0, SeekOrigin.Begin);
 				// Check for unexpected control characters that shouldn't be present in a text file and can crash this plugin
-				foreach(byte b in testArray)
+				bool twoConsecutiveNulls = false;
+				for(int i = 0; i < 512; i++)
 				{
-					if(b < 0x20 && b != 0x0A && b != 0x0D && b != 0x00)
+					if(i >= imageFilter.GetDataForkStream().Length)
+						break;
+
+					if(testArray[i] == 0)
+					{
+						if(twoConsecutiveNulls)
+							return false;
+						twoConsecutiveNulls = true;
+					}
+					else
+						twoConsecutiveNulls = false;
+
+					if(testArray[i] < 0x20 && testArray[i] != 0x0A && testArray[i] != 0x0D && testArray[i] != 0x00)
 						return false;
 				}
 
diff --git a/DiscImageChef.DiscImages/CDRWin.cs b/DiscImageChef.DiscImages/CDRWin.cs
index 907c7fec..333677f3 100644
--- a/DiscImageChef.DiscImages/CDRWin.cs
+++ b/DiscImageChef.DiscImages/CDRWin.cs
@@ -320,9 +320,22 @@ namespace DiscImageChef.ImagePlugins
 				imageFilter.GetDataForkStream().Read(testArray, 0, 512);
 				imageFilter.GetDataForkStream().Seek(0, SeekOrigin.Begin);
 				// Check for unexpected control characters that shouldn't be present in a text file and can crash this plugin
-				foreach(byte b in testArray)
+				bool twoConsecutiveNulls = false;
+				for(int i = 0; i < 512; i++)
 				{
-					if(b < 0x20 && b != 0x0A && b != 0x0D && b != 0x00)
+					if(i >= imageFilter.GetDataForkStream().Length)
+						break;
+					
+					if(testArray[i] == 0)
+					{
+						if(twoConsecutiveNulls)
+							return false;
+						twoConsecutiveNulls = true;
+					}
+					else
+						twoConsecutiveNulls = false;
+					
+					if(testArray[i] < 0x20 && testArray[i] != 0x0A && testArray[i] != 0x0D && testArray[i] != 0x00)
 						return false;
 				}
 
diff --git a/DiscImageChef.DiscImages/CloneCD.cs b/DiscImageChef.DiscImages/CloneCD.cs
index 6f5faab7..a70e2b88 100644
--- a/DiscImageChef.DiscImages/CloneCD.cs
+++ b/DiscImageChef.DiscImages/CloneCD.cs
@@ -127,9 +127,22 @@ namespace DiscImageChef.DiscImages
 				imageFilter.GetDataForkStream().Read(testArray, 0, 512);
 				imageFilter.GetDataForkStream().Seek(0, SeekOrigin.Begin);
 				// Check for unexpected control characters that shouldn't be present in a text file and can crash this plugin
-				foreach(byte b in testArray)
+				bool twoConsecutiveNulls = false;
+				for(int i = 0; i < 512; i++)
 				{
-					if(b < 0x20 && b != 0x0A && b != 0x0D && b != 0x00)
+					if(i >= imageFilter.GetDataForkStream().Length)
+						break;
+
+					if(testArray[i] == 0)
+					{
+						if(twoConsecutiveNulls)
+							return false;
+						twoConsecutiveNulls = true;
+					}
+					else
+						twoConsecutiveNulls = false;
+
+					if(testArray[i] < 0x20 && testArray[i] != 0x0A && testArray[i] != 0x0D && testArray[i] != 0x00)
 						return false;
 				}
 
diff --git a/DiscImageChef.DiscImages/GDI.cs b/DiscImageChef.DiscImages/GDI.cs
index ee0ed256..f60a3f03 100644
--- a/DiscImageChef.DiscImages/GDI.cs
+++ b/DiscImageChef.DiscImages/GDI.cs
@@ -138,9 +138,22 @@ namespace DiscImageChef.ImagePlugins
 				imageFilter.GetDataForkStream().Read(testArray, 0, 512);
 				imageFilter.GetDataForkStream().Seek(0, SeekOrigin.Begin);
 				// Check for unexpected control characters that shouldn't be present in a text file and can crash this plugin
-				foreach(byte b in testArray)
+				bool twoConsecutiveNulls = false;
+				for(int i = 0; i < 512; i++)
 				{
-					if(b < 0x20 && b != 0x0A && b != 0x0D && b != 0x00)
+					if(i >= imageFilter.GetDataForkStream().Length)
+						break;
+
+					if(testArray[i] == 0)
+					{
+						if(twoConsecutiveNulls)
+							return false;
+						twoConsecutiveNulls = true;
+					}
+					else
+						twoConsecutiveNulls = false;
+
+					if(testArray[i] < 0x20 && testArray[i] != 0x0A && testArray[i] != 0x0D && testArray[i] != 0x00)
 						return false;
 				}
 				gdiStream = new StreamReader(imageFilter.GetDataForkStream());