Since, as pointed out in the above post, I haven't uploaded directly to Youtube in years. I export the file and then upload it to youtube.

What about if you export as a file to a folder?  

Oh! I see the difference. Screenshot of your export settings would be great.

You can only put one screen shot per post unless you combine them into one.

I mention TaskManager because it's something that most will be able to have a handle on. There is a sample movie project, The Sky Is The Limit.... ?>Load Sample Movie See if you can export it. 

...too easy!

How big is the file? There is a size limit and only one image per post. With Reaper recording live 20 tracks, fx, routing on a notebook. The only way to know what is going on is open TaskManager and see CPU and RAM usage while working. 

If you want help and it was asked for you to provide a screenshot, it might help in getting an idea of what your problem is. Also, delete Rendered files (Setup>Control Panel>Storage Locations) and rename your project. Turn OFF Hardware Acceleration too.

First, how to add a SCREENSHOT to your post. I would change the Optimization to 50 and Acceleration to NONE or INTEL and see what happens. What also happens is the stress put on a computer when it's rendering. When I Export, I can hear the fans on the radiator (water cooled) starting to ramp up to keep things cool. I'll have CPU usage at ...

First, how to add a SCREENSHOT to your post. Now, make a screen shot of the Export tab. Also, why AVI? Did you try any of the other formats? What is the resolution of the video? Can you provide a short clip to the cloud so that I and others can download and see if it's just a problem at your end or global issue?