diff --git a/pytensor/configdefaults.py b/pytensor/configdefaults.py
index 673d41039f..e383646949 100644
--- a/pytensor/configdefaults.py
+++ b/pytensor/configdefaults.py
@@ -348,7 +348,7 @@ def add_compile_configvars():
         if sys.platform == "win32":
             mingw_w64_gcc = Path(sys.executable).parent / "Library/mingw-w64/bin/g++"
             try:
-                rc = call_subprocess_Popen([mingw_w64_gcc, "-v"])
+                rc = call_subprocess_Popen([str(mingw_w64_gcc), "-v"])
                 if rc == 0:
                     maybe_add_to_os_environ_pathlist("PATH", mingw_w64_gcc.parent)
             except OSError:
diff --git a/pytensor/utils.py b/pytensor/utils.py
index 1f33300629..3943cc612c 100644
--- a/pytensor/utils.py
+++ b/pytensor/utils.py
@@ -123,7 +123,7 @@ def maybe_add_to_os_environ_pathlist(var: str, newpath: Path | str) -> None:
         pass
 
 
-def subprocess_Popen(command, **params):
+def subprocess_Popen(command: str | list[str], **params):
     """
     Utility function to work around windows behavior that open windows.
 
@@ -131,11 +131,11 @@ def subprocess_Popen(command, **params):
     """
     startupinfo = None
     if os.name == "nt":
-        startupinfo = subprocess.STARTUPINFO()
+        startupinfo = subprocess.STARTUPINFO()  # type: ignore[attr-defined]
         try:
-            startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
+            startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW  # type: ignore[attr-defined]
         except AttributeError:
-            startupinfo.dwFlags |= subprocess._subprocess.STARTF_USESHOWWINDOW
+            startupinfo.dwFlags |= subprocess._subprocess.STARTF_USESHOWWINDOW  # type: ignore[attr-defined]
 
         # Anaconda for Windows does not always provide .exe files
         # in the PATH, they also have .bat files that call the corresponding