diff --git a/scripts/patch_vm_disk_replace.py b/scripts/patch_vm_disk_replace.py
new file mode 100644
index 0000000..c8db48b
--- /dev/null
+++ b/scripts/patch_vm_disk_replace.py
@@ -0,0 +1,74 @@
+#!/usr/bin/env python3
+from pathlib import Path
+import sys
+
+app_path = Path(sys.argv[1]) if len(sys.argv) > 1 else Path('/opt/virtuality/web/app.py')
+if not app_path.exists():
+    raise SystemExit(f'app.py not found: {app_path}')
+
+text = app_path.read_text()
+changed = []
+
+helper = r'''
+
+def vm_exists(name: str) -> bool:
+    if not name or not valid_vm_name(name):
+        return False
+    return run_cmd(["virsh", "dominfo", name], timeout=8)["ok"]
+'''
+if 'def vm_exists(name: str) -> bool:' not in text:
+    marker = '\n\ndef list_vms() -> list[dict[str, str]]:'
+    if marker not in text:
+        raise SystemExit('list_vms marker not found')
+    text = text.replace(marker, helper + marker, 1)
+    changed.append('vm_exists helper added')
+else:
+    changed.append('vm_exists helper already present')
+
+old_sig = 'def vm_create_submit(request: Request, name: str = Form(...), memory: int = Form(...), vcpus: int = Form(...), disk_size: int = Form(...), iso_path: str = Form(""), disk_image_path: str = Form(""), source_type: str = Form("iso"), guest_arch: str = Form("auto"), network_mode: str = Form("nat"), bridge: str = Form(DEFAULT_BRIDGE)):'
+new_sig = 'def vm_create_submit(request: Request, name: str = Form(...), memory: int = Form(...), vcpus: int = Form(...), disk_size: int = Form(...), iso_path: str = Form(""), disk_image_path: str = Form(""), source_type: str = Form("iso"), guest_arch: str = Form("auto"), replace_existing_disk: str = Form("0"), network_mode: str = Form("nat"), bridge: str = Form(DEFAULT_BRIDGE)):'
+if old_sig in text:
+    text = text.replace(old_sig, new_sig, 1)
+    changed.append('replace_existing_disk added to signature')
+elif 'replace_existing_disk: str = Form("0")' in text:
+    changed.append('replace_existing_disk already in signature')
+else:
+    raise SystemExit('vm_create_submit signature marker not found')
+
+old_form = 'form = {"name": name, "memory": memory, "vcpus": vcpus, "disk_size": disk_size, "iso_path": iso_path, "disk_image_path": disk_image_path, "source_type": source_type, "guest_arch": guest_arch, "network_mode": network_mode, "bridge": bridge}'
+new_form = 'form = {"name": name, "memory": memory, "vcpus": vcpus, "disk_size": disk_size, "iso_path": iso_path, "disk_image_path": disk_image_path, "source_type": source_type, "guest_arch": guest_arch, "replace_existing_disk": replace_existing_disk, "network_mode": network_mode, "bridge": bridge}'
+if old_form in text:
+    text = text.replace(old_form, new_form, 1)
+    changed.append('replace_existing_disk stored in form')
+elif '"replace_existing_disk": replace_existing_disk' in text:
+    changed.append('replace_existing_disk already stored in form')
+
+old_disk_check = '''    disk_path = IMAGES_DIR / f"{name}.qcow2"
+    if disk_path.exists():
+        return vm_form_context(request, error=f"Диск уже существует: {disk_path}", form=form, status_code=400)
+
+    profile = host_profile.load_host_profile()
+'''
+new_disk_check = '''    disk_path = IMAGES_DIR / f"{name}.qcow2"
+    if vm_exists(name):
+        return vm_form_context(request, error=f"VM с именем {name} уже существует. Выбери другое имя или удали существующую VM.", form=form, status_code=400)
+    if disk_path.exists():
+        if replace_existing_disk == "1":
+            disk_path.unlink()
+        else:
+            return vm_form_context(request, error=f"Диск уже существует: {disk_path}. Это может быть остаток неудачной установки. Включи опцию «Заменить существующий диск», если VM с таким именем не нужна.", form=form, status_code=400)
+
+    profile = host_profile.load_host_profile()
+'''
+if old_disk_check in text:
+    text = text.replace(old_disk_check, new_disk_check, 1)
+    changed.append('disk replace logic added')
+elif 'Заменить существующий диск' in text and 'replace_existing_disk == "1"' in text:
+    changed.append('disk replace logic already present')
+else:
+    raise SystemExit('disk_path exists marker not found')
+
+app_path.write_text(text)
+print('vm disk replace patch applied:')
+for item in changed:
+    print(f'- {item}')