Cubase 15 Crash on project exit

Cubase
1

Hi Folks,

That happens on two projects now. Please take a look at that screenshot.

Simple project, only few tracks, just started working on it. my mixer window is opened on the 2nd monitor (as always)

Spec:

Windows 11, 64 GB RAM (no issue with system resources)

I noticed Cubase is unloading the project and the mixer parallely. Could it be connected?

thanks,

Itai

Cubase 15 crash 2026-09-13 091930
Cubase 15 crash 2026-09-13 0919301358×809 129 KB

2

If that helps,

The plugIn on the unloading channel is Omnisphere

3

If you can please post the crash dump file here. Look for it in your Documents folder → Steinberg → Crash Dumps

4

There is no crash dump for this event. But I found one from few weeks back. It is probably related to the other project I mentioned crashing on exit.

hope that helps,

thanks,

Cubase Artist 15.0.30 64bit 2026.8.16 18.29.37.263-freezedump.dmp (2.2 MB)

5

Claude analyzed for me.

In short: “The UI thread is blocked on Steinberg’s licensing/media client, which is waiting on the network.”

But that is your old freeze dump, and doesn’t really line up with the screen shot above.

Next time, when Cubase hangs, you can right-click it in task manager and choose “create memory dump”

Pete
Microsoft

6

Thanks for looking into it,

As you suggested, I created dump file out of Cubase crash. It turned out to be very big in size (5.7 GB) so I couldn’t upload it through this chat window

you can access it here

Thanks,

7

You need to open that Google drive file to everyone.

Pete
Microsoft

8

I thought I did,

Please try this link

thanks,

9

This is what Copilot said it was after analyzing the crash dump. I recommend filing a bug directly with Steinberg and include a link to that dmp file.

HEAP_CORRUPTION_ACTIONABLE_BlockNotBusy_DOUBLE_FREE_80000003_ucrtbase.dll!free_base

Cubase called free() on a block that was already free. RtlFreeHeap caught it (“BlockNotBusy”), raised a fatal failure, and the thread is now parked in WER while it writes the dump. That’s why all 409 threads are waiting and it presents as a freeze — WER suspends the process to capture 5.8 GB.

Below free_base there are ~30 consecutive frames of Cubase15.exe and nothing else. No third-party DLL, no plugin, no MIDI component anywhere in the freeing path. This is a double free in Steinberg’s own code.

Pete
Microsoft

10

Nice! I will look for opening a ticket.

I suspect it is a shared memory between the two unloading threads :slight_smile:

thanks @Psychlist1972 !! appreciate the effort!

Anyone here from Steinberg support monitoring this conversation?

Could you please pass it on to Engineering?

@Johnny_Moneto ?

thanks,