is the only recourse to create a whole series of custom rendering profiles
Yes, if you use them all. I'm used to check rendering template every time I start render. It's not a big issue to fix this and that in this case. If you are going to render using dozens of templates a day it might be better to scan them all.

As for GPU settings in options - it's is quite different story. It applies not to rendering GPU acceleration, but to video FX acceleration.

The error occurs when any of the MainConcept MP4 project settings templates are used (perhaps others, too, but these are my go-to output templates). I can 'customize' the template and turn "Encode mode" from 'automatic' to 'CPU only,' but I have to do this every time I render, since you can't save the templates (you can of course rename and save as a *new* template, but rather than duplicate all of my settings templates, I'd rather just solve the problem).

I would also expect that if you centrally turn GPU rendering off in "Preferences" that this would override all of the template 'automatic' settings, but that does not seem to be the case. So I really don't know what the purpose of that Preferences setting is.

This seems to have started happening right after updating my video drivers. So if there's something about the Radeon drivers that is making Vegas unhappy, I have to believe others would experience this...?

It applies not to rendering GPU acceleration, but to video FX acceleration.

Ahh, that explains that, at least -- thanks!

Just a few thoughts. If it worked with an earlier driver, why don't you go back to that driver? Even for Nvidia cards like my GTX580 I am using a very "old" driver to make it all work. The difference between GPU ON and OFF is like day and night in terms of render speed and timeline performance. There are endless posts in this forum on why and how. The MC AVC templates should not be left on "Automatic" but rather set to the correct GPU; in your case that would mean to set it to OPEN GL. I also made my own templates to ensure that CUDA is selected and not automatic. The easiest is to make those templates and make them you favorites, this way to don't have always look for them.

The error message is a result of Windows being unable to open the file. Let's get the obvious out of the way first. Do you have plenty of room on your project drive and the TEMP drive (usually C:)? Does the mp4 file already exist? Try manually deleting the old file. Also, reinstall Vegas.

"this PC has an ATI Radeon HD5700 series card in it."

Did you previously have an nVidia card installed? If so, did you delete all traces of nVidia drivers and software?

There are 2 locations to control GPU acceleration inside Vegas 11 & 12. There is the overall GPU acceleration setting that is found under the preferences which accelerates preview, fx and even renders of certain CODECS. There is also additional CUDA acceleration settings at the CODEC options in the "Render As" menu.

Did you ever install a codec pack?

I'm thinking I could try rolling back the driver as a last resort.

This PC never had an NVidia card in it -- this is the original card.

There's plenty of open space on my hard drives. The PC in question is a dedicated video editing machine and I keep it very clean.

I will look into the CUDA setting, I'm not familiar with that. Thanks!

You don't have to look too hard at CUDA since you've never had an NVidia adapter in the machine. CUDA is a name for NVidia's hardware.

If you look at the System tab on the render template, there is a Check GPU button that will let you know what render assistance Is available. One might find CUDA, OpenCL or QSV (intel Quicksync).

I think my post wasn't clear. For an AMD card like your 5700 you have to select "Open CL" in the render template; don't leave it on Auto. CUDA is only for Nvidia.

Ah, I gotcha -- sorry, I wasn't familiar with "CUDA."

When I click the "Check GPU" button under the templates' System tab, it says, "OpenCL is available." I presume that's why the program tries to use it when the Encode Moe is set to "automatic (recommended)," but since the ATI driver update, it fails. It seems like perhaps ATI "did something" to the new driver that reports that it is available, but it no longer is...?

I can't be the only person this has happened to, since there are YouTube videos about how to fix the problem... I wonder if MainConcept or Sony is working with ATI to figure out what happened.

Okay, I decided to roll back the video driver.

Afterward, I started up Vegas and it immediately stopped working before the program screen even appeared. The error referenced "\AppData\Local\Sony\Vegas Pro\11.0\gpu_video_x64.log" which was telling. I opened that and it looks like it jammed on: INFO 2013-12-12 06:08:04 OpenCL_Initialize. I rarely have good luck rolling back drivers.

The app then suggested I install the latest build, and directed me to the download page. Although... that's the build I am already running. I'm going to reinstall it anyway to see if perhaps it cleans something up.

Of course, if that works, I may be tempted to update the video driver again and try again, but that may get e into a vicious circle. We'll see.

@dvddude
So you are back to the driver that worked before and it still doesn't work? Sounds like the newer driver wasn't completely uninstalled. BTW… would you mind filling out your complete system spec? It makes it easier to help you.

Right. I used Device Manager to roll back the video driver to the previous version, and that seemed to really upset Vegas. So I reinstalled the latest ATI driver again, and Vegas is back to working, but also back to choking on the Render mode being 'automatic' (i.e., using the GPU). I uninstalled and reinstalled Vegas, too, hoping that maybe it would "see" whatever is different about the video driver during install, but there's no change.

It really seems like something is amiss between the new ATI(AMD) Catalyst driver and the MainConcept module.

My system:

Motherboard: ASUS ROG Maximus III Formula
CPU: i7 K875 @2.93 GHz
RAM: 8 GB
OS: Windows 7 64-bit
Drives: 4 conventional disk drives (WD 2TB)
Graphics: AMD Radeon HD 5700 series
Sound: AMD HD (onboard)

Windows Experience Indices:
CPU: 7.5
RAM: 7.5
Graphics: 7.3
Gaming: 7.3
HDD: 5.9

Thanks for giving this some thought!

I think I mentioned earlier in one of my posts that it should not be left in Automatic, try setting it to OpenCL for your AMD card. You can also try to reset Vegas by holding down CTRL+Shift during start; note that it will reset any presets you have made too. Why didn't you reinstall, not roll back, the driver that worked?

I also found this in the forum http://www.sonycreativesoftware.com/forums/ShowMessage.asp?Forum=4&MessageID=848219

I'm not sure I understand. The only three choices in the dropdown list for "Encode mode" are:

-Automatic (recommended)
-Render using CPU only
-Render using GPU if available

I don't see any explicit references to OpenCL.

I will see if I can get a copy of the old driver and reinstall that way, but it bothers me to have to set the entire PC back to an older driver because one app doesn't like the new one. I try to keep everything up to date. In fact, I updated the video drivers recently because that solved a problem I was having in Windows Explorer with R-click functionality. You know, I'd even consider buying a whole new video card if I was sure that it would solve the problem, but it really seems to me that the issue is the MainConcept drivers not talking to the AMD/ATI drivers, not everything else in my system. Am I wrong? The reason I even zeroed-in on the video driver being the issue is because there are posts and YouTube videos showing how to get rid of the error message, so I know others are having the same problem.

If you are using Mainconcept AVC rendering template then it should look like this https://drive.google.com/file/d/0Bz4okF1D_ux5MzRLRVRFUmVkZk0/edit?usp=sharing