Okay, I know I just saw someone else having this issue, but it suddenly happened to me today. I thought it might be the video files from my S10+ since some where in that slo-mo mode so I ran them through XMedia Recode (an output that has never failed to be compatible with Hitfilm) but I still get the error that it failed to initialize ACC Encoder (Error #32) So, I tried a PNG sequence and, of course with no sound component, it was fine, so I tried MOV and it is also fine and rendering as I type. What gives? Has the recent update from Micro*(&*()&^ thrown a spanner into the works for Hitfilm? I will be even more unhappy with Gates and company than I already am if that new Edge (which I don't use anyway) has bollocksed up an often used program!
Edit: Davlon clued me in to his recent thread about this and his solution in this thread here for those who find this later: