Is the PC connected to the internet? Vegas needs to 'phone home' occasionally to verify codec licenses and such.
You could use Voukoder to encode the project, or just the AAC audio and mux that in. Voukoder's FDK-AAC encoder is probably better than the MainConcept (or default) encoder anyway. The Nero AAC encoder is highly regarded as well.

Hey all. Yes to the "run as administrator". No change.

And yes, it is connected to Internet. Vegas briefly throws up a clock-like "Activating License", so I imagine it's at that point that it's trying to phone home.

Possibly a firewall blocking the internet communication?

OK, in this forum your communication ended without any solution! :( I have the same problem. I can import only file directlly from my Sony a7IV camera, but any other, like rendered to 1920x1080 or 4K, returns this error "The activation of AAC (MC) failed." :( Thera are many chats about this problem, but only useles bla, bla, bla ideas! Is there any admin or moderator from Magix? I can't belive that it's unsolved from old versions like 16! Should we really change Vegas for Premiere or not?

I have the same problem. I still can't find a solution anywhere. All means have been used, but nothing helps.

@Kauko-Suominen The previous posts suggest an internet or server problem. Possibly the complainants were successful when later trying again but didn't come back to inform us? The Magix server unfortunately probably isn't 100% reliable.

Do you get the "Vegas briefly throws up a clock-like "Activating License" experience previously mentioned?

What is that activation web address and name in Europe? I would check if VP16 is trying to the correct address.

Since the trial version of VP21 and VP10 and dozens of other programs work flawlessly on my computer, it is clear that VP16 is buggy and that's why codec activation often stops working. Magix hasn't been very helpful in solving these problems and so it feels like this is intentional in order to sell updates.

Definitely not intentional- Magix doesn't break software after the fact and actually had sales on VP 16 years after it was released as a "HumbleBundle."

Maybe temporarily disable a firewall and see if it works?

The firewall has been turned off and the antivirus has been temporarily removed. Special rights have been given to the firewall. Started as administrator. VP16 has been reinstalled many times, the internet connections of the activation have been examined and so on. Nothing helps. It's amazing because all other applications except VP16 work on the computer without any problems. I got only general instructions from Magix Support, which didn't help. According to Google searches, many other users have not been helped by them either. No further instructions are available.

No one has even answered this question: What is that activation web address and name in Europe? I would check if VP16 is trying to the correct address.

No one has even answered this question: What is that activation web address and name in Europe? I would check if VP16 is trying to the correct address

@Kauko-Suominen It's unlikely any forum members will have the answer to that. Try emailing Magix at infoservice@magix.net.

No one has even answered this question: What is that activation web address and name in Europe? I would check if VP16 is trying to the correct address.

You may be able to find that out, since you've obviously had some experience.

https://www.wireshark.org/

I haven't received any help from Magix. Only these advices about running as an administrator but not working. I should obviously do a clean install of Windows, but when the big job and everything else works. I have tried many types of security or access rights settings. I asked Magix for a description of the working mechanism of codec activation, but I haven't received any answer. Since this is a real problem for many users, I think I could have received better help. Either they don't know or they want to sell upgrades.

Since this is a real problem for many users, I think I could have received better help. Either they don't know or they want to sell upgrades.

Actually, it's probably a real problem for a handful of users. I've not been seeing "many" reporting this issue, only a very few.

I read somewhere that someone had tried for 2 months without success. As will I soon. Yes, there are quite a few whose VP16 has stopped using codecs quite unexpectedly and nothing else helps but a clean installation of Windows. I have been working with computers since the 1980s, and I have never seen any other application that is so persistently inoperable.

What about installing it using a new Windows user account?

@Kauko-Suominen said: "...nothing else helps but a clean installation of Windows. I have been working with computers since the 1980s, and I have never seen any other application that is so persistently inoperable.?"

If you're been working with computers that long, surely, you must have heard of saving a system image of your boot drive. I restore my most current image after I work on some of the bugs here where I try things that I wouldn't otherwise ever do.

It always amazes me how many people on the planet seem to prefer to shoot bugs more than doing maintenance.

An Aside

I also replace the tires on my vehicles after five years without regard to whether there is any wear or damage to the tires.

• As tires age, they are more prone to failure. Some vehicle and tire manufacturers recommend replacing tires that are six to 10 years old, regardless of treadwear. You can determine how old your tire is by looking on the sidewall for your DOT Tire Identification Number (TIN) . The last four digits of the TIN indicate the week and year the tire was made. If the TIN reads 0308 it was made in the third week of 2008. Look on both sides of the tire. The TIN may not be on both sides.

I am a hobbyist and only do what is necessary. It has never been necessary to take such bold actions. The restore point has saved me a couple of times now. Now it seems hopeless to get VP16 working, since no more in-depth instructions have come from Magix.

You tried uninstalling VEGAS, creating a new Windows user account with admin privileges and installing it again?

Otherwise maybe it is time to move on and not waste any more of your time.

Yes. It's really sad when I've paid for this and now it's completely unusable. A small consolation is that VP 10 works flawlessly on this same machine. I think it shows that VP16 is buggy when all other programs work without problems. Seems like a waste of time but I would like to resolve this.

Did you try the new user account?

Disabling the firewall?

Yes. All such normal actions tried.

Do you have another computer?

VP 10 likely didn't activate codecs on first use. VEGAS does that now as there are more codecs that cost money and the price of the software has gone down, so it's a way to save money. For most of us it's seamless and the codec we need gets activated instantly.