Unsigned Driver Issue

I have a File System Filter driver that we have designed and built. We went
through the signing process and have received the signed .cat files from

I have a custom installer application (32-bit) for our product. When I try
and install the driver with this installer application, it goes through the
entire process of installing it and completes. Looking at the setupapi.app
log file there was no error in there. However, after a number of moments the
“Program Compatibility Assistant” message box appears saying that “Windows
requires a digitally signed driver”.

I have run “signtool verify /v /kp /c dnafsmonitor.cat dnafsmonitor.sys” and
it seems to verify fine without errors.

When I check security event logs, it says:
“Code integrity determined that the image hash of a file is not valid.”

If i check the CodeIntegraty section of the Event Viewer it says :
“Windows is unable to verify the image integrity of the file
\Device\HarddiskVolume1\Windows\System32\drivers\dnaFSMonitor.sys because
file hash could not be found on the system. A recent hardware or software
change might have installed a file that is signed incorrectly or damaged, or
that might be malicious software from an unknown source.”

I am at a loss as to what to do and generating a support ticket from here in
Australia is driving me crazy.

Thanks for the help.

Also, I find it strange that when I install using the SetupAPI it doesn’t fall over there. Normally, if you try to install an unsigned driver, the SetupAPI blocks the installation altogether. If I check the SetupAPI.app logs it all installed fine.