When I try to import MPEG4 files, I get the error message "Activation of the AAC (MC) function failed". I have already written several times with the support, but there was almost nothing and the suggestions (allow Vegas in firewall etc.) have not helped either. I have Vegas 18, 19 and 20 on my computer and it doesn't work with any versions anymore. Complete reinstallations and start as administrator etc. were also unsuccessful. Even deactivation of my computer and reactivation on the vegas account webpage didnt help.I didn't change anything about the system or Vegas, so I guess it came with a Windows update, because before that I could use Vegas for 20 years (since version 8) without getting such errors. I have also searched in various other forums, there were also people with this problem from time to time. Something was said about a registry entry. But that didn't help me either. I also get a similar error message for MPEG2 files. I had already tried to convert the MPEG4 files via an online video converter, but also without success. I'm quite annoyed because I actually need the software for work, but I haven't been able to use it for months. That's why I temporarily switched to DaVinci Resolve. This has NO problems with ANY video file. It's really an indictment of poverty that the support doesn't help here, and sometimes just doesn't answer anymore. Does anyone have an idea what else I could do? I guess it's just that the audio codec can't be activated, do I understand that correctly?