>>>>As for the SMB issues, I've deactivated SMB v2/3 on the (virtual) server, but doing so also prevent the users from accessing the server.
>>>
>>>That hints for me to deactivated SMB1 - perhaps double check ?
>>>You NEED SMB to access remote files, but only SMB1 is ISAM safe...
>>
>>If I understand you correctly, I should deactivate SMB2/3 and let only SMB1 activated?
>>
>Correct

Hmm, SMB1 has multiple nasty security vulnerabilities and has been deprecated in Windows for a long time. Disabling SMB2/3 is not recommended and reduces functionality of more recent versions of Windows:

https://support.microsoft.com/en-us/help/2696547/how-to-detect-enable-and-disable-smbv1-smbv2-and-smbv3-in-windows-and

Specifically, the warning and header information at the top of that link.

As a sysadmin my preference is to disable SMB1 unless it's needed by really old devices or Windows versions, leave SMB2/3 enabled, and apply the Alaska Software registry changes to workstations and/or session servers.