Avast! Free Antivirus 7.0 hangs the system when trying to detect a newly created virus

The antivirus works almost without any issues, service starts correctly, all secturity modules include real-time protection works fine and updating a virus databse to the latest version is succesfull. But detecting a newly created viruses hangs the system. I made a simple test virus:
1. Create a new text document in any folder.
2. Put into him the following line:

X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*

3. Then save and exit.
4. Rename the file extension to .com. After this ReactOS hangs if Avast is running. Probably antivirus detects a file correctly but wherein he hangs the system.
After force reboot antivirus doesn't detect this file as a virus, but file extension is alrady renamed to .com.
In XP Avast detects the file correctly without any freezes or reboots (shows notification). In ROS he doesn't show any notifications and doesn't play builtin sounds. Maybe trying to show the notification causes a freeze?