diff --git a/scripts/build-all b/scripts/build-all
index d3a1c68..d6cef26 100755
--- a/scripts/build-all
+++ b/scripts/build-all
@@ -26,6 +26,9 @@ templeos_iso_file = home_path + 'iso/TempleOS.ISO'
 
 qemu_run_cmd = qemu_bin_path + ' ' + qemu_display + ' -enable-kvm -m 1024 -cdrom ' + qemu_slipstream_iso_file + ' -audiodev pa,id=snd0 -machine pcspk-audiodev=snd0 -debugcon stdio -boot d'
 
+def kill_running_qemu_processes():
+    os.system('killall -e "' + qemu_bin_path + '"')
+
 def clang_format_src_files():
     print("build-all: clang-format-src-files")
     exclude_paths = ["mujs", "openlibm", ".iso.c"]
@@ -140,6 +143,7 @@ def run():
         raise ValueError("build-all: step 'run' failed, error code " + str(res))
 
 def build_all():
+    kill_running_qemu_processes()
     clang_format_src_files()
     refresh_build_path()
     build_libtemple()