Maybe you've done all of what I'm about to say, but I'll say it because I encountered difficulty when I installed the Legacy Firewire driver in Win10.

I assume you've followed the instructions from a site like https://www.studio1productions.com/Arti … wire-1.htm and downloaded the file you need from https://www.studio1productions.com/down … Driver.msi

Once I downloaded it, I thought that all I needed to do open the Windows Device Manager, select the "1394 IEEE..." entry, select "Update Driver" and then navigate to this file. This never worked.

I eventually found I had to double click on the .msi file, and while it appears to install the driver, all it really does is create a folder named "1394 OHCI Compliant Host Controller (Legacy)" in your C:/Program Files (x86) folder, and deposits the necessary driver files there - one set for 32 bit and for 64 bit Windows systems - you'll need to know which you're running.

Next, run the Device Manager and "Update" the 1394 Driver by navigating to the folder located in the Programs (x86) folder, and selecting either the x86 or x64 version, depending on which type of Windows system you're running. The Device Manager should not crash when it is told to do this - at least it didn't on my machine. You'll know whether you've succeeded if the Device Manager entry for the 1394 IEEE device has "(Legacy)" at the end of its name. You need to re-boot the computer to finish the change.

I apologize if this is just a tedious re-cap of everything you've tried already, but it did cause me grief until I realized that it's a two stage operation.