Corrupt a DMG File Online
Corrupt a macOS .dmg disk image online for free. Destroys the koly trailer and block map so the image cannot be mounted or verified.
- Без загрузки на сервер
- Без ограничения размера
- Без регистрации
Испортите свой файл DMG
Настроено под .dmg, .sparseimage, и так же работает с любым другим форматом.
Почему файлы DMG трудно испортить как следует
A DMG is a UDIF image read from the very end of the file: a 512-byte koly trailer points at the XML block map that describes every compressed run. Destroy the trailer and macOS has no idea where anything is, regardless of how intact the rest of the image happens to be.
Что разрушает этот инструмент
- The koly trailer. The 512-byte UDIF trailer in the last block of the file is destroyed. This alone makes the image unmountable.
- The mish block map. The block descriptors mapping compressed runs to disk offsets are overwritten.
- The XML property list. The embedded plist describing partitions and checksums is destroyed.
- Image payload. Entropy is scattered through the compressed data so nothing can be carved out.
Что вы увидите после
| Приложение | Поведение |
|---|---|
| Finder / DiskImageMounter | "No mountable file systems" or "image not recognized." |
hdiutil attach | "resource temporarily unavailable" or a checksum verification failure. |
| Disk Utility | Verification fails and the image is reported as invalid. |
| Gatekeeper | Never reached, the image fails before any signature check. |
Частые причины это сделать
- Testing that a macOS installer pipeline verifies images before mounting them.
- Verifying a software updater handles a corrupt download and retries.
- Reproducing a "damaged disk image" support scenario for a runbook.
- Checking that image checksums are actually validated rather than assumed.
Как испортить файл DMG
- Перетащите файл .dmg в поле выше или нажмите, чтобы выбрать.
- Оставьте уровень Standard, если вам не нужно частичное повреждение (Light) или победа над программами восстановления (Heavy).
- Нажмите Испортить файл. Обработка идёт на вашем устройстве, поэтому заканчивается почти мгновенно.
- Скачайте результат. По умолчанию он сохраняет исходное имя файла и длину в байтах.
Вопросы о DMG
Why is the koly trailer so important?
Because UDIF images are read backwards. macOS looks at the final 512 bytes to find the block map that describes the whole image, without it, nothing else in the file can be located.
Will Disk Utility repair it?
No. Disk Utility repairs filesystems inside a mountable image. This image never mounts, so there is nothing for it to work on.
Does it work on encrypted DMGs?
Yes. The encrcdsa header is targeted along with the standard UDIF structures.
Are large images handled?
Yes. Processing runs in slices, so multi-gigabyte images work without exhausting browser memory.