This post has been updated in march 2015 and is only valid for CANUSB using our own PID FFA8, if you have a newer CANUSB (we started to ship out them in February 2015) we changed PID to standard FTDI 6001 so off the shelf signed FTDI drivers could be used instead of our modified for our PID. Please read this post for more information on newer CANUSB with PID 6001 and how to verify which you have.
Below is original post from January 28th 2013. Read and use only if you have a CANUSB with PID FFA8.
We have now tested CANUSB together with Windows 8 (and later versions) and there are some things to think of when you use Windows 8. Our test PC is using Windows 8.1 Pro on 64bit but it will be same on all versions. We have updated this post with some new information as well, see bottom of this post.
Due to the requirement in Windows 8 (and later versions), that all drivers need to be signed, the FTDI driver for CANUSB will not be installed unless you change some settings in Windows 8. Please also note that in the writing of this the FTDI drivers are not approved for Windows 8 according to their web. But even if FTDI drivers later will be approved and signed for Windows 8, we need to unpack them and edit info for our CANUSB (add info for PID=0xFFA8), then pack them again and put here for download, this means they will be unsiged again. We will not send off drivers to be signed at Microsoft each time FTDI releases a new driver, it will be a costy procedure for us. This was not a problem in Windows 7, where unsigned drivers could be installed if you just said yes to the question you got, but in Windows 8 it is diffrent.
The instructions here is at your own risk, but it is easy to make Windows 8 to accept non signed drivers. You can force Windows 8 by doing the following below.
We have found this post to be the best on how to install unsigned drivers in Windows 8, so try this first before doing anything below!
If the above doesn’t work here are some other help:
Open a Command Promt (cmd) as Administrator and type the following 2 commands:
bcdedit -set loadoptions DISABLE_INTEGRITY_CHECKS
bcdedit -set TESTSIGNING ON
With bcdedit you are configuring the boot menu of Windows, so be careful. If something goes wrong wou will need a Windows DVD to repair the bootmanager.
After a restart you can go to device manager and choose to update the FTDI driver by right clicking on CANUSB and choose to update driver, point to where you downloaded the driver and all is OK.
When FTDI USB driver is installed you can turn off this again by starting the Command Promt (cmd) as Administrator and type the following 2 commands:
bcdedit -deletevalue loadoptions
bcdedit -deletevalue TESTSIGNING
And you are back to the default values after you have restarted Windows 8. This two procedures only apply to the FTDI USB driver, our own CANUSB DLL driver do not need to be signed, it is only drivers related to hardware.
Unsure how to run cmd as an Administrator, check this post. It is not as easy as just log in as an Administrator, you need to start it as well with Administrator privileges.
There are also other ways todo this since we originally wrote this post, if you follow this links and/or this link for some valuable information on how to install unsigned drivers in Windows 8 (and later versions). You might even before you do the above on some new PC's click the “Clear Security Bits” in the BIOS.