Can't use VirtualBox VM when an interface is managed by VirtualBox

[ghost]

GNS3 version 2.1.1dev1 on Darwin (64-bit) with Python 3.6.3 Qt 5.9.2 and PyQt 5.9.1, VirtualBox V5.1.14

https://www.gns3.com/qa/gns3-2-1-interface-already-confi

Having a VirtualBox image with the first adapter managed by VirtualBox and starting it gives error message Attachment (nat) already configured on adapter 1. Please set it to 'Not attached' to allow GNS3 to use it..

Even using it alone without any connection gives that result.

Here the VirtualBox network configuration, adapter 1 is connected to NAT, the other 3 adapters are not connected:

And here the VM configuration in GNS3, nothing special:

The same sort of network configuration (one interface not managed by GNS3) works with VMware.

Here the GNS3 server log:

2017-11-13 20:38:31 INFO helpers.py:508 192.168.1.10 - - [13/Nov/2017:19:38:31 +0000] "GET /v2/appliances HTTP/1.1" 200 17274 "-" "GNS3 QT Client v2.1.1dev1"
2017-11-13 20:38:31 INFO helpers.py:508 192.168.1.10 - - [13/Nov/2017:19:38:31 +0000] "GET /v2/appliances/templates HTTP/1.1" 200 443674 "-" "GNS3 QT Client v2.1.1dev1"
2017-11-13 20:38:31 INFO project.py:80 Project 36af8060-0696-4416-baa0-df6622a37dba with path '/Users/behlers/GNS3/projects/untitled' created
2017-11-13 20:38:31 INFO helpers.py:508 192.168.1.10 - - [13/Nov/2017:19:38:31 +0000] "POST /v2/compute/projects HTTP/1.1" 201 282 "-" "Python/3.6 aiohttp/2.2.5"
2017-11-13 20:38:31 INFO __init__.py:102 Executing VBoxManage with command: /Applications/VirtualBox.app/Contents/MacOS/VBoxManage --nologo list systemproperties
2017-11-13 20:38:31 INFO virtualbox_vm.py:190 VirtualBox VM 'Ostinato-1' [694f39b3-2c00-4467-a122-56df4c2adfd4] created
2017-11-13 20:38:31 INFO __init__.py:102 Executing VBoxManage with command: /Applications/VirtualBox.app/Contents/MacOS/VBoxManage --nologo showvminfo Ostinato --machinereadable
2017-11-13 20:38:31 INFO virtualbox_vm.py:685 VirtualBox VM 'Ostinato-1' [694f39b3-2c00-4467-a122-56df4c2adfd4] can have a maximum of 8 network adapters for chipset PIIX3
2017-11-13 20:38:31 INFO virtualbox_vm.py:697 VirtualBox VM 'Ostinato-1' [694f39b3-2c00-4467-a122-56df4c2adfd4] has changed the number of Ethernet adapters to 4
2017-11-13 20:38:31 INFO __init__.py:102 Executing VBoxManage with command: /Applications/VirtualBox.app/Contents/MacOS/VBoxManage --nologo showvminfo Ostinato --machinereadable
2017-11-13 20:38:31 INFO helpers.py:508 192.168.1.10 - - [13/Nov/2017:19:38:31 +0000] "POST /v2/compute/projects/36af8060-0696-4416-baa0-df6622a37dba/virtualbox/nodes HTTP/1.1" 201 702 "-" "Python/3.6 aiohttp/2.2.5"
2017-11-13 20:38:31 INFO helpers.py:508 192.168.1.10 - - [13/Nov/2017:19:38:31 +0000] "POST /v2/projects/36af8060-0696-4416-baa0-df6622a37dba/appliances/0918df2a-8436-485d-9a65-8565ae541497 HTTP/1.1" 201 236 "-" "GNS3 QT Client v2.1.1dev1"
2017-11-13 20:38:34 INFO __init__.py:102 Executing VBoxManage with command: /Applications/VirtualBox.app/Contents/MacOS/VBoxManage --nologo showvminfo Ostinato --machinereadable
2017-11-13 20:38:34 INFO __init__.py:102 Executing VBoxManage with command: /Applications/VirtualBox.app/Contents/MacOS/VBoxManage --nologo showvminfo Ostinato --machinereadable
2017-11-13 20:38:34 INFO __init__.py:102 Executing VBoxManage with command: /Applications/VirtualBox.app/Contents/MacOS/VBoxManage --nologo showvminfo Ostinato --machinereadable
2017-11-13 20:38:34 INFO base_node.py:699 VirtualBox: 'Ostinato-1' [694f39b3-2c00-4467-a122-56df4c2adfd4]:local UDP tunnel created between port 10000 and 10001
2017-11-13 20:38:34 ERROR route.py:210 Node error detected: VirtualBoxError
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/gns3_server-2.1.1dev1_135c529-py3.6.egg/gns3server/web/route.py", line 195, in control_schema
    yield from func(request, response)
  File "/usr/local/lib/python3.6/site-packages/gns3_server-2.1.1dev1_135c529-py3.6.egg/gns3server/handlers/api/compute/virtualbox_handler.py", line 186, in start
    yield from vm.start()
  File "/usr/local/lib/python3.6/site-packages/gns3_server-2.1.1dev1_135c529-py3.6.egg/gns3server/compute/virtualbox/virtualbox_vm.py", line 267, in start
    yield from self._set_network_options()
  File "/usr/local/lib/python3.6/site-packages/gns3_server-2.1.1dev1_135c529-py3.6.egg/gns3server/compute/virtualbox/virtualbox_vm.py", line 852, in _set_network_options
    adapter_number + 1))
gns3server.compute.virtualbox.virtualbox_error.VirtualBoxError: Attachment (nat) already configured on adapter 1. Please set it to 'Not attached' to allow GNS3 to use it.
2017-11-13 20:38:34 INFO helpers.py:508 192.168.1.10 - - [13/Nov/2017:19:38:34 +0000] "POST /v2/compute/projects/36af8060-0696-4416-baa0-df6622a37dba/virtualbox/nodes/694f39b3-2c00-4467-a122-56df4c2adfd4/start HTTP/1.1" 409 428 "-" "Python/3.6 aiohttp/2.2.5"
2017-11-13 20:38:34 INFO helpers.py:508 192.168.1.10 - - [13/Nov/2017:19:38:34 +0000] "POST /v2/projects/36af8060-0696-4416-baa0-df6622a37dba/nodes/start HTTP/1.1" 409 363 "-" "GNS3 QT Client v2.1.1dev1"

[grossmj]

Fixed in GNS3/gns3-server@b14e2e7