diff --git a/src/Microsoft.PowerShell.Commands.Diagnostics/PdhHelper.cs b/src/Microsoft.PowerShell.Commands.Diagnostics/PdhHelper.cs
index 97eff22db0d..ff2b7621403 100644
--- a/src/Microsoft.PowerShell.Commands.Diagnostics/PdhHelper.cs
+++ b/src/Microsoft.PowerShell.Commands.Diagnostics/PdhHelper.cs
@@ -7,7 +7,7 @@
 using System.Diagnostics;
 using System.Globalization;
 using System.Runtime.InteropServices;
-
+using System.Text;
 using Microsoft.PowerShell.Commands.GetCounter;
 using Microsoft.Win32;
 
@@ -531,20 +531,38 @@ public uint ConnectToDataSource(string dataSourceName)
             return res;
         }
 
-        public uint ConnectToDataSource(StringCollection blgFileNames)
+        public uint ConnectToDataSource(List<string> blgFileNames)
         {
             if (blgFileNames.Count == 1)
             {
                 return ConnectToDataSource(blgFileNames[0]);
             }
 
-            string doubleNullTerminated = string.Empty;
-            foreach (string fileName in blgFileNames)
+            int length = blgFileNames.Count + 1;
+            for (int i = 0; i < blgFileNames.Count; i++)
             {
-                doubleNullTerminated += fileName + '\0';
+                length += blgFileNames[i].Length;
             }
 
-            doubleNullTerminated += '\0';
+            string doubleNullTerminated = string.Create(length, blgFileNames, (buf, fileNames) =>
+            {
+                int pos = 0;
+                for (int i = 0; i < fileNames.Count; i++)
+                {
+                    string fileName = fileNames[i];
+                    int fileNameLength = fileName.Length;
+                    fileName.AsSpan().CopyTo(
+                        buf.Slice(pos, fileNameLength));
+                    pos += fileNameLength;
+                    buf[pos] = '\0';
+                    pos++;
+                }
+
+                buf[pos] = '\0';
+                pos++;
+
+                Debug.Assert(pos == length, "Error constructing double null terminated string.");
+            });
 
             return ConnectToDataSource(doubleNullTerminated);
         }