diff --git a/kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/KotlinNativeTest.kt b/kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/KotlinNativeTest.kt
index 438c6f00044..3c167c6d4ec 100644
--- a/kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/KotlinNativeTest.kt
+++ b/kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/KotlinNativeTest.kt
@@ -380,7 +380,7 @@ open class KonanDriverTest : KonanStandaloneTest() {
             it.print("Konanc compiler execution:")
             project.file("$executable.compilation.log").run {
                 writeText(it.stdOut)
-                writeText(it.stdErr)
+                appendText(it.stdErr)
             }
             check(it.exitCode == 0) { "Compiler failed with exit code ${it.exitCode}" }
         }