Index: Migration/Scripts/src/Migration.Scripts.Data/UpgradeScript.cs
===================================================================
diff -u -r56e690b056dd0901609e651f6ac3c010d3d002b7 -r85ff91388190d242a5bd74e110b2c5f8b177bff3
--- Migration/Scripts/src/Migration.Scripts.Data/UpgradeScript.cs	(.../UpgradeScript.cs)	(revision 56e690b056dd0901609e651f6ac3c010d3d002b7)
+++ Migration/Scripts/src/Migration.Scripts.Data/UpgradeScript.cs	(.../UpgradeScript.cs)	(revision 85ff91388190d242a5bd74e110b2c5f8b177bff3)
@@ -93,8 +93,15 @@
         /// <exception cref="CriticalMigrationException">Thrown when upgrading failed.</exception>
         public void Upgrade(string sourceLocation, string targetLocation)
         {
-            IOUtils.ValidateFilePath(sourceLocation);
-            IOUtils.ValidateFilePath(targetLocation);
+            if (!IOUtils.IsValidFilePath(sourceLocation))
+            {
+                throw new ArgumentException($@"'{sourceLocation}' is not a valid file path.", nameof(sourceLocation));
+            }
+            if (!IOUtils.IsValidFilePath(targetLocation))
+            {
+                throw new ArgumentException($@"'{targetLocation}' is not a valid file path.", nameof(targetLocation));
+            }
+
             PerformUpgrade(sourceLocation, targetLocation);
         }