I've used Vegas 14 Pro (and earlier versions) for a few years without issue. I recently got MS 17 Plat since it can render 1440p in a fraction of the time 14 Pro can, using the GPU. I started getting video/audio sync issues, at random, usually off by a second or so, but NOT on all videos. I know from researching that this is pretty common.
Captured from pc gaming with Shadowplay by Nvidia. I've been reading up and it seems the consensus is it has to do with the variable bit rate Shadowplay uses. That may be, but I'm not convinced unless 17 has given something up that 14 has.
Here's what's odd: I can pretty easily manually sync it back up sliding the video back and lopping off the front end of the clip and the rest is sync'd up. Compressing the video to run faster/shorter by that second difference *doesn't* seem to sync it. I don't see how it can actually be recording video longer than audio due to experimenting with Vegas 14 Pro and *the same file*, which works perfectly. The issue seems to be something that 14 Pro has or does that MS 17 does not, rather than an issue with the video itself. Unless it's an issue that 14 could just deal with.
Comparing 14 to 17, 17 doesn't seem to have nearly as many options for project properties as 14 Pro, I don't know enough to know if it's just streamlined or if it's lacking. I've compared preferences (ctrl+preferences) and my untrained eyes don't see anything that stands out, but I keep thinking there's something in there that's enabled on 14 Pro that is not present or enabled on MS 17.
That's a wall of text, but I prefer too much info to yet another post with no real info asking for help. I don't know if this can is legible or not, but it compares 2 files that have the sync issue in 17 and the third on the right did NOT have the issue. All 3 worked just fine in 14 Pro with no issues. I can post a video showing this as well, but I don't want to come across as self-promoting.
Thank you if you read all of that. If still awake and have thoughts about what might need to be enabled on 17, or is completely missing (maybe on Pro?) please let me know.
EDIT: short answer, it had to do with taking shortcuts. Add video properly to project media first and then to the timeline took care of it. I don't know why it worked perfectly in 14 Pro and requires the additional step in 17, but I'm sure it's good form to do it this way and the problem has tested as solved.