How to reproduce:
1. Download the Origin web installer 10.4.17 for Windows 7 here: https://www.filehorse.com/download-origin/31637/download/
2. Extract it by any archiver and launch OriginThinSetupInternal.exe from the directory where you extracted it.
3. After the installer launchs, click "Install Origin", then uncheck all checkboxes except "Create a desktop link" and "Create a Start Menu link" and check "I agree with Origin's EULA", and finally click "Continue".
4. Wait while it will be downloaded and installed. After the installation is finish, reboot the system.
5. Now launch Origin and login into your account without checking the "Remember me" button, because it may cause another filesystem damage in some cases. For me it is not always reproducible.
6. After you logined and there opens the main window, download Mass Effect 3 Demo via the Origin client, or copy it from the host OS if it is present there to the C:\Program Files\Origin Games\ directory by default (I acted like this). Maybe it also can be reproducible with any other game, but I cannot test this, because I don't have another compatible games with ReactOS in Origin, except Mass Effect 3 Demo.
7. When downloading will finished, install it by clicking "Install" in the popup menu which appears when you dirtect the mouse cursor on the game preview. There also may be appear an error associated with DirectX. Ignore this error, and try to install the game again. For me it installs correctly only after the third attepmt.
8. When it installs correctly, reboot the system again to save the registry settings.
9. Now open Origin again, login into it, and try to launch the game. After this, the system immediately hangs with the assertion in ntoskrnl and the following entering kdb:
Also there are many spam in the log associated with fastfat, which probably indicates a problem:
and something else:
Tested with g1f95439 (0.4.10-dev-89).