I'd love to leave it unchecked, and will try doing so again.. until I can't.

On both my new Dell laptop and my 3YO desktop, the only way we can get through stable editing these past few jobs is with it checked -- otherwise we were getting crashes every 5-10 minutes, significantly hampering our productivity and causing hair loss in the process ;-) Kidding aside, constant crashing makes ppl want to leave the platform, so the relief from checking the box and avoiding crashes -- was needed. And we're not alone.. other users reported similar.

I'd love to leave it unchecked, and will try doing so again.. until I can't.

On both my new Dell laptop and my 3YO desktop, the only way we can get through stable editing these past few jobs is with it checked -- otherwise we were getting crashes every 5-10 minutes,

The AVC file that you can't load with b370 using legacy decoder you could load with b326 using legacy decoder?

There's a number of AVC camera files that can't be loaded by legacy decoder because it doesn't know about more modern codecs. The main crashing problem was the use of hardware decoding on Vegas, you can use the new decoder without using hardware decoding by selecting 'hardware decoder to use' to off. You still had this crashing every 5-10mins with vp20b326 when using hardware decoder?

In my limited testing a while ago, I noticed legacy decoder was more efficient (CPU wise) than new decoder when not using hardware decoder, that is more of a problem for your Core i7-7700K, but shouldn't be noticeable on your i7-12700H

The reason I don't use hardware decoding (where possible) is due to timeline performance, it lags more on edit points with GPU decoder on, this problem has existed since VP15

I'd love to leave it unchecked, and will try doing so again.. until I can't.

On both my new Dell laptop and my 3YO desktop, the only way we can get through stable editing these past few jobs is with it checked -- otherwise we were getting crashes every 5-10 minutes,

<...snip...> The main crashing problem was the use of hardware decoding on Vegas, you can use the new decoder without using hardware decoding by selecting 'hardware decoder to use' to off. You still had this crashing every 5-10mins with vp20b326 when using hardware decoder?

Yes. Both 326 and the latest build -- I just tried on a new project I'm finishing up.

If hardware decoding is set to "off" (not choosing any GPU) it still crashes often.. very unproductive. Checking "use legacy decoder" and it's solid/reliable. Note I also did enable video acceleration on the "video" tab and things are going smoothly -- as long as "legacy decoder" is checked.

I understand you're saying that not using legacy and setting it to "none", you'd think, would make for stable editing, but it doesn't for us here.

Worth noting -- setting "use legacy decoder" and setting the decoder to "None" aren't doing exactly the same thing.

Why do I say that?

When you enable the Legacy Decoder, Vegas rebuilds all the audio peaks. If you disable it, it will rebuild them again. It doesn't do that when simply setting decoder to "None".

So there's still some different processing being done under the hood regardless of if the hardware decoder is set to "none". There's a bug in there somewhere which causes instability on both my laptop and desktop, and as reported here, some other users are experiencing too.