If a newer version of the client is installed on a 64 bit Windows OS, it will prevent an older version of the client with the same driver version number from being installed later. This does not occur on 32 bit OSs.

The problem is related to the oemXXX.inf file which is created by windows automatically when a new driver is installed. It would appear that 32 bit Windows operating systems do a better job of updating infs when the driver version number is identical. If subsequent driver package is installed with an identical version number but a different catalog signature, the older inf and catalog files are referenced. This causes the signature check to fail when operating system attempts to load the driver. We currently re-sign the driver catalog before each installation which is undesirable.

The only way to correct this issue is to remove any lingering Shrew Soft oemXXX.inf files from the windows inf path before re-installing the software.

The process of building a release install needs to be de-coupled from building and signing the driver releases. This is the only good long term solution. Each catalog should be built and signed once to avoid multiple conflicting copies.