diff --git a/tool/agent-upgrade-dist/src/main/kotlin/Files.kt b/tool/agent-upgrade-dist/src/main/kotlin/Files.kt
index db76bee9..759b6457 100644
--- a/tool/agent-upgrade-dist/src/main/kotlin/Files.kt
+++ b/tool/agent-upgrade-dist/src/main/kotlin/Files.kt
@@ -8,8 +8,8 @@ fun File.dir(): Sequence<File> = this.listFiles()?.asSequence() ?: emptySequence
 
 fun File.ensureDirExists(description: String = "", createIfNotExists: Boolean = false): File {
     if (this.exists()) {
-        if (this.isDirectory) {
-            throw Exception("\"$this\" - is not a directory.");
+        if (!this.isDirectory) {
+            throw Exception("\"$this\" - is not a directory.")
         }
         return Paths.get(path).toRealPath().toFile()
     }