Hi Martin,
Yesterday I recorded a days session to discover afterwards that VMX was accedentally started twice. This resulted in no audio on the recording. Everything else was OK, so we didn't notice any difference (audio and video OK) in VMIX only to discover later there was no audio on the recorded video.

Is it possible (because useless) to prevent VMIX from starting a second instance, or to have a message displayed that a second instance is started.

I alway look at the way VMIX is starting: it should be quick and smooth. Sometimes however startup is slow, maybe related to the hardware and composition I use (Laptop i7 SSD, USB3 BM shuttle etc). I then restart the system and restart VMIX. When it's quick and smooth I load the preset and setup my recording. Once in a while however a second instance can be started accidentally or by clicking two times, or a click and enter, or something.

PS I was able to fix the recording because I record a master on the camera and was able to use the recorded sound, but sync is poor at the end.
greetings Stefan