iMac freezing and crashing while using OBS, NDI, Skype, YouTube

Hello Skatz the Singer,

From the sound of your post, it appears the Mac is not performing as expected. There are a couple of things we want to check.

Let's start by making sure there is at least 30 GB or 15% of the hard drive free. The computer uses this space to operate. You can find ways to increase disk space here: How to free up storage space on your Mac

It is also important that the macOS is up to date. How to update the software on your Mac

Let's try starting up the system in what is called safe mode. To start in safe mode, begin with the computer powered off. Press the power button to turn it on then press and hold the Shift key. Keep holding the shift key until you get to the log in screen. More information is available here: How to use safe mode on your Mac. The computer will take longer to start in safe mode, and the screen may have some distorted video as it starts up. This is normal. When starting in safe mode, the computer performs a check of your startup disk. If everything seems to startup as expected, go ahead and restart the computer normally and test.

If issues continue, go ahead and reset the System Management Controller. The SMC is responsible for managing behaviors related to multiple systems. How to reset the SMC of your Mac

Next, reset the NVRAM by Pressing Command-Option-P-R while restarting the Mac. Hold the keys until the Mac restarts. Reset NVRAM or PRAM on your Mac

These steps can help resolve issues involving the computer not running as efficiently as it should.

We hope this helps.

Have a wonderful day!

Hi,

quite a lot to report, strange things are happening! Thanks for the advice for a start.

Storage: attached screenshot shows something weird, I’ve hardly got anything on my SSD but there’s only half of it free.

Is that anything to do with the other screenshot (duplicate HD) that appears on startup?

That’s only happened since updating to Big Sur so it can’t be the source of the crashing, unless it’s a future quantum drive that’s travelled backwards in time. (I watch too much Star Trek).

OS is up to date, I’ve only just installed Big Sur after reformatting the HD. (That duplicate HD is an issue others have noticed, I read an article about it. However I didn’t want to get sidetracked with it.)

Now onto the weirdness:

Okay, when I start in safe mode, the first thing I notice is my second monitor (Samsung TV) is showing No Signal.

When I start up OBX the video is stuttering (looks like it’s only running at 1 or 2 frames per second)

There’s a delay and stuttering when I click, grab and move any window.

Also there are no Sound Output devices found on System Preferences.

I started up a Skype with my wife and she couldn't hear me. The video of her was stuttering too.

Then the system froze and crashed and restarted.

So I thought I'd send you this now. Hopefully that will tell you something. It definitely didn't look or act 'Safe'!

..after that I went on to reset the SMC and the NVRAM and tried again but the problem still persists.

I had Activity Monitor on during the freeze so I took a photo of the screen with my phone, so I've attached that in case it help diagnose.

From what I said on the previous message it sounds like an audio and video issue, or whatever controls the two of them. Should I be talking to Apple? Is it a hardware problem?

What's also just piqued my interest, when I went to Airdrop the photo from my phone it showed up 2 iMacs, one called Andrew's iMac, which is the one in question that received the photo, the other called Skatz's iMac, which is what I put as my user name. Is that something to do with the duplicate HD? It could be totally unrelated.