diff --git a/BuildCompat.py b/BuildCompat.py
index e3470dd2ad..cc38ed3f9c 100644
--- a/BuildCompat.py
+++ b/BuildCompat.py
@@ -1,12 +1,11 @@
 #!/usr/bin/python3
 import os
-from twisted.python.filepath import FilePath
-from subprocess import Popen
 import re
 import sys
+import asyncio
+from pathlib import Path
 
 tm = '-m' in sys.argv
-
 parallel = '-j' in sys.argv
 
 PROJECT_PATTERN = re.compile(r'''Project.".[0-9A-Za-z]{8}-[0-9A-Za-z]{4}-[0-9A-Za-z]{4}-[0-9A-Za-z]{4}-[0-9A-Za-z]{12}.". = '''
@@ -16,30 +15,41 @@
 
 PUBLICIZER = os.environ.get("PUBLICIZER", "./AssemblyPublicizer")
 DOWNLOAD_LIBS = os.environ.get("DOWNLOAD_LIBS", "--download-libs")
-tasks = []
-
-def system(*cmd):
-    sp = Popen(cmd)
-    if not parallel:
-        sp.wait()
-        ec = sp.poll()
-        if ec:
-            raise SystemExit(ec)
-    else:
-        tasks.append(sp)
-
-with open("Source/CombatExtended.sln") as f:
-    for line in f.readlines():
-        line = line.strip()
+
+async def run_command(*cmd):
+    proc = await asyncio.create_subprocess_exec(*cmd)
+    await proc.wait()
+    if proc.returncode != 0:
+        raise SystemExit(proc.returncode)
+
+async def main():
+    tasks = []
+
+    async def process_line(line):
         match = PROJECT_PATTERN.match(line)
         if match:
             name, csproj = match.groups()
-            if tm and name not in sys.argv: continue
-            csproj = csproj.replace('\\', '/').split('/')
-            csproj = FilePath("Source").descendant(csproj)
+            if tm and name not in sys.argv:
+                return
+            csproj_path = Path("Source").joinpath(*csproj.split('/')).as_posix()
             print(f"Building {name}")
-            output = FilePath("AssembliesCompat").child(name+".dll")
-            system("python3", "Make.py", "--csproj", csproj.path, "--output", output.path, DOWNLOAD_LIBS, "--all-libs", "--publicizer", PUBLICIZER, "--", "-r:Assemblies/CombatExtended.dll")
+            output_path = Path("AssembliesCompat").joinpath(f"{name}.dll").as_posix()
+            cmd = [
+                "python3", "Make.py", "--csproj", csproj_path, "--output", output_path,
+                DOWNLOAD_LIBS, "--all-libs", "--publicizer", PUBLICIZER, "--",
+                "-r:Assemblies/CombatExtended.dll"
+            ]
+            if parallel:
+                tasks.append(run_command(*cmd))
+            else:
+                await run_command(*cmd)
+
+    with open("Source/CombatExtended.sln") as f:
+        for line in f:
+            await process_line(line.strip())
+
+    if parallel:
+        await asyncio.gather(*tasks)
 
-for t in tasks:
-    t.wait()
+if __name__ == "__main__":
+    asyncio.run(main())