Hi there!
I got the same problem as
@MisterSic but unfortunately I don't get how he solved the problem. I am recording with OBS by using a dual PC setup. My laptop is only working on the recording and the PC is only in charge for the games. My laptop's CPU usage (I record via x264 encoder) is around 30% all the time and I am saving the files on a 3 TB USB 3.0 drive which is only meant to store these big files (but is never even half full as I convert the files to MP4 right after recording).
So my issue can be described in the same way as MisterSic did in his first post: I record 1-2 hours and all the time OBS seems to work well (recording ongoing and the preview screen shows everything I see on my monitor). Just when I open the files, some of them are missing content. One time I recorded a little more than 2 hours and VLC player showed only a 53 min. video. There I can see that just before it's being cut, I don't do anything special like pressing any buttons on my laptop which could cause this problem. Adobe Premiere Pro at least showed that the video is actually this 2 hours + long but in minute 53 it's turning black and the audio stops. The same happened today - at first I recorded around 50 minutes without any problem. Then I started another recording which lastet around 1 hour 15 minutes. The video seems to be cut in VLC at 1 hours 3 minutes. After having read MisterSic's comment, that he's using Virtual Dub to restore the AVI's I gave that one a try and see there: This software shows the whole length of the video incl. the minutes that are missing according to VLC.
One of my first thoughts was that for some reason my elgato HD60S capture card is somehow going to some kind of sleep mode after 1 hour but that doesn't make sense as is this case at least my webcam should still be recorded.
This really is a pain in the a** because I never know if a recording was successful or if I have to take additional 2 hours to restore the file with Virtual Dub. Enclosed you can find the log file from today's recording (which "stopped" at 1 hour 3 min.). Hope anyone can help me on this. If you need more information, feel free to ask.
Thanks in advance,
alex