Hi.
I'm having trouble getting the rosetta python projects task to work with an error at start.
I'm getting the error with the VBoxManager command.
I'm not sure why the error occurs only when I run the command from BOINC Client, while there is no error when I run commands such as

sudo -u boinc VBoxManage -q list hostinfo

directly.
boinctui says

Task aaae-mVAL_pp-TIQ_pp-mNMVAL-ACHA14C_2874422_9_1 postponed for 86400 seconds: Communication with VM Hypervisor failed. Communication with VM Hypervisor failed.

The following error is printed in /var/lib/boinc-client/slots/8/stderr.txt.

VBoxManage: error: Failed to create the VirtualBox object!
VBoxManage: error: Code NS_ERROR_SOCKET_FAIL (0xC1F30200) - IPC daemon socket error (extended info not available)
VBoxManage: error: Most likely, the VirtualBox COM server is not running or failed to start.

I built VirtualBox and Boinc from source.

$ boinc --version
7.21.0 x86_64-pc-linux-gnu

$ VBoxManage --version
7.0.0_ALPHA1r95556

(I am translating from Japanese by DeepL Translator. Sentence may not correct. Sorry.)

I'm having simiilar issue; postponed for 86400 seconds; Code NS_ERROR_SOCKET_FAIL (0xC1F30200)

tasks :
1491839286
1491839339
1491838813

Manjaro Linux 5.10.129-1-MANJARO|libc 2.35
Boinc 7.18.0
Virtual Box 6.1.34

stderr log of task 1491839286 (timestamp is UTC+9)

<core_client_version>7.18.0</core_client_version>
<![CDATA[
<message>
aborted by user</message>
<stderr_txt>
2022-07-20 13:13:18 (4269): vboxwrapper (7.7.26197): starting
2022-07-20 13:13:24 (4269): Error in guest additions for VM: -1041038848
Command:
VBoxManage -q list systemproperties
Output:
VBoxManage: error: Failed to create the VirtualBox object!
VBoxManage: error: Code NS_ERROR_SOCKET_FAIL (0xC1F30200) - IPC daemon socket error (extended info not available)
VBoxManage: error: Most likely, the VirtualBox COM server is not running or failed to start.

2022-07-20 13:13:24 (4269): Feature: Checkpoint interval offset (241 seconds)
2022-07-20 13:13:24 (4269): Detected: VirtualBox VboxManage Interface (Version: 6.1.34)
2022-07-20 13:13:30 (4269): Error in host info for VM: -1041038848
Command:
VBoxManage -q list hostinfo 
Output:
VBoxManage: error: Failed to create the VirtualBox object!
VBoxManage: error: Code NS_ERROR_SOCKET_FAIL (0xC1F30200) - IPC daemon socket error (extended info not available)
VBoxManage: error: Most likely, the VirtualBox COM server is not running or failed to start.

2022-07-20 13:13:30 (4269): WARNING: Communication with VM Hypervisor failed.
2022-07-20 13:13:30 (4269): Could not communicate with VM Hypervisor. Rescheduling execution for a later date.

</stderr_txt>
]]>

This thread is currently on "Cafe rosetta" topic,
but should be located at "Number crunching" topic?

# I didn't notice when I wrote my previous post

Oh, sorry. Should I recreate this thread at "Number crunching" topic?

Maybe so :-)
Number crunching topic is more suitable for technical trouble, bug report, etc.

I seem to have found a workaround!

1. Open systemd unit file to edit

sudo systemctl edit boinc-client

2. In the new contents section, type

[Service]
PrivateTmp=true

then save and exit.

3. Reload systemd and restart boinc-client.

sudo systemctl daemon-reload
sudo systemctl restart boinc-client

reference : [Solved] Virtualbox and NS_ERROR_SOCKET_FAIL (LHC@home)

This worked for me and crunching some virtualbox tasks normally so far. Hope this helps.