RPC_S_SERVER_UNAVAILABLE when closing down VirtualBox GUI before virtual machine starts (regression)

[bobJ]

Problem description:

1. In Oracle VM VirtualBox Manager (GUI tool) click on virtual machine and then Start button.
2. Because I don't need VirtualBox Manager GUI anymore I close it down.
3. Like 2 to 3 seconds later I get error:

Failed to open a session for the virtual machine <vm name> and Details: Callee RC: RPC_S_SERVER_UNAVAILABLE/0x800706ba (0X800706BA)

It looks to me this problem only appears if VirtualBox Manager is closed down before virtual machine is getting started.

If I wait for few seconds and the virtual machine's window appears before I close down VirtualBox Manager, it looks like error never appears.

This problem started to happen now that after using VirtualBox 6.1 for years I upgraded directly to VirtualBox 7.0.2.

I am very used to closing down VirtualBox Manager after I click on Start virtual machine button. It gets supper annoying that I get this error, because I just forget that now for some reason I have to wait before virtualbox machine GUI appears.

It looks like a regression in v7.0 comparing to v6.1.

My host is: Windows 10 My guest is: Ubuntu 22.04

[bobJ]

I deleted all of the files from my virtual machine Logs folder and retested the problem. I am attaching VBoxHardening.log file. VBox.log file does not exists yet when this problem appears.

[fth0]

Other users have reported that with VirtualBox 7.0.(0|2?), the VM's window needs significantly longer to appear, which could be related to your observations. If you keep the VirtualBox Manager running, what's the first timestamp in the VBox.log file like?

[bobJ]

I have deleted all files from Logs directory and started virtual machine. First line from VBox.log is:

00:00:03.170265 VirtualBox VM 7.0.2 r154219 win.amd64 (Oct 19 2022 21:29:26) release log

[fth0]

Ok, then it's probably unrelated and you're just too fast. ;) (I've seen startup times in the range of 10 seconds up to 4 minutes.)

PS: I'm not affiliated to Oracle or the VirtualBox development, so do not consider my engagement as official reply.

[bobJ]

I don't think I should be too fast. I have another computer with VirtualBox 6.1.40 and I did an experiment. I prepared myself with keyboard and with mouse. In VirtualBox Manager I selected virtual machine and then clicked on Start button. Immediately few microseconds I pressed Alt+F4 and VirtualBox Manager closed down and then virtual machine started just normally.

I assume there is something "new" in VirtualBox 7.0.2 (I haven't installed and tested on 7.0.0) that requires VirtualBox Manager to be up and running after Start button is pressed and until particular virtual machine GUI window appears.

[asottile]

I am also experiencing this defect in 7.0.6 -- this is quite annoying as I start VMs pretty often and will probably keep me on the 6.x line until fixed