diff --git a/tests/TestHarness/Node.py b/tests/TestHarness/Node.py
index f58d9259f8..0511899723 100644
--- a/tests/TestHarness/Node.py
+++ b/tests/TestHarness/Node.py
@@ -527,6 +527,12 @@ def launchCmd(self, cmd: List[str], data_dir: Path, launch_time: str):
         err = dd / Path(f'stderr.{launch_time}.txt')
         pidf = dd / Path(f'{Utils.EosServerName}.pid')
 
+        # make sure unique file name to avoid overwrite of existing log file
+        i = 0
+        while err.is_file():
+            i = i + 1
+            err = dd / Path(f'stderr.{launch_time}-{i}.txt')
+
         Utils.Print(f'spawning child: {" ".join(cmd)}')
         dd.mkdir(parents=True, exist_ok=True)
         with out.open('w') as sout, err.open('w') as serr: