IT-Grundschutz Scans not authenticating via SMB

Posting in Source, since this is from a source build.

Run into a problem with IT-Grundschutz; the SMB-based tests keeps failing SMB logons. However, all other non-IT-Grundschutz scans are authenticating successfully via SMB, so authentication is working ok. The SMB/WMI consolidated results are:

Description (Knowledge base entry) Value/Content

Access to the registry possible (SMB/registry_access) : TRUE
Access via WMI possible (WMI/access_successful) : TRUE
Architecture of the OS (SMB/Windows/Arch) : x64
Build number of the OS (SMB/WindowsBuild) : 7601
Disable file search via WMI on Windows (win/lsc/disable_wmi_search) : FALSE
Disable the usage of win_cmd_exec for remote commands on Windows (win/lsc/disable_win_cmd_exec) : FALSE
Domain used for authenciated scans (kb_smb_domain()) : Empty/None
Enable Detection of Portable Apps on Windows (win/lsc/search_portable_apps) : FALSE
Extended SMB support available via openvas-smb module (Tools/Present/smb) : TRUE
Extended WMI support available via openvas-smb module (Tools/Present/wmi) : TRUE
Login via SMB failed (login/SMB/failed) : FALSE
Login via SMB successful (login/SMB/success) : TRUE
Missing access permissions to the registry (SMB/registry_access_missing_permissions) : FALSE
Name of the most recent service pack installed (SMB/CSDVersion) : Service Pack 1
Never send SMB credentials in clear text (SMB/dont_send_in_cleartext) : TRUE
Only use NTLMv2 (SMB/dont_send_ntlmv1) : FALSE
Path to the OS SystemRoot (smb_get_systemroot()) : C:\Windows
Path to the OS SystemRoot for 32bit (smb_get_system32root()) : C:\Windows\system32
Port configured for authenciated scans (kb_smb_transport()) : 445/tcp
Port used for the successful login via SMB : 445/tcp
Product name of the OS (SMB/WindowsName) : Windows 7 Professional
SMB name used for authenciated scans (kb_smb_name()) :
User used for authenciated scans (kb_smb_login()) : remote
Version number of the OS (SMB/WindowsVersion) : 6.1
Workgroup of the SMB server (SMB/workgroup) : WORKGROUP

Any suggestions on where to look?

Closing as a duplicate of the newly created (and more detailed) topic below.