diff --git a/qt/python/mantidqt/mantidqt/dialogs/errorreports/run_pystack.py b/qt/python/mantidqt/mantidqt/dialogs/errorreports/run_pystack.py
index 12bcd2fe1545..6078207cb06f 100644
--- a/qt/python/mantidqt/mantidqt/dialogs/errorreports/run_pystack.py
+++ b/qt/python/mantidqt/mantidqt/dialogs/errorreports/run_pystack.py
@@ -106,7 +106,7 @@ def _decompress_lz4_file(lz4_core_dump_file: Path) -> Path:
     tmp_decompressed_core_file = NamedTemporaryFile()
     with lz4.frame.open(lz4_core_dump_file.as_posix(), "r") as lz4_fp:
         tmp_decompressed_core_file.write(lz4_fp.read())
-    return tmp_decompressed_core_file
+    return Path(tmp_decompressed_core_file.name)
 
 
 def _is_lz4_file(core_dump_file: Path) -> bool: