diff --git a/vlib/os/os_nix.c.v b/vlib/os/os_nix.c.v
index 648aa2affc..0766d2af2f 100644
--- a/vlib/os/os_nix.c.v
+++ b/vlib/os/os_nix.c.v
@@ -211,3 +211,8 @@ pub fn is_writable_folder(folder string) ?bool {
 	os.rm(tmp_perm_check)
 	return true
 }
+
+[inline]
+pub fn getpid() int {
+	return C.getpid()
+}
diff --git a/vlib/os/os_windows.c.v b/vlib/os/os_windows.c.v
index 78f4f9bec6..270f093123 100644
--- a/vlib/os/os_windows.c.v
+++ b/vlib/os/os_windows.c.v
@@ -378,7 +378,7 @@ pub fn is_writable_folder(folder string) ?bool {
 	if !os.is_dir(folder) {
 		return error('`folder` is not a folder')
 	}
-	tmp_perm_check := os.join_path(folder, 'tmp_perm_check')
+	tmp_perm_check := os.join_path(folder, 'tmp_perm_check_pid_' + getpid().str())
 	mut f := os.open_file(tmp_perm_check, 'w+', 0o700) or {
 		return error('cannot write to folder $folder: $err')
 	}
@@ -386,3 +386,9 @@ pub fn is_writable_folder(folder string) ?bool {
 	os.rm(tmp_perm_check)
 	return true
 }
+
+fn C._getpid() int
+[inline]
+pub fn getpid() int {
+	return C._getpid()
+}