Great Bug?!

[tsetselee]

apparently, many people has the same problem as me, when installing SPTD 1.25, "system file error"
the error seems to be UN-ERASEABLE register key and unable to uninstall it.

Hope DuplexSecure can release an "uninstall" for us.

[Digger]

You MUST remove/disable SPTD layer first and reboot, then you can remove that key. If SPTD layer is running, that key is protected against any unauthorized access, including deletion.
Either rename SPTD.sys, run SPTD stand-alone installer with remove option, or disable SPTD service in registry. Check our FAQ regarding SPTD service:
http://duplexsecure.com/faq/
Ensure you reboot afterwards, BEFORE you try to install again.