I have a fresh installation of the currrent openHABian version on my PI 3.
If I try to connect to the smb shares the Windows 7 Explorer chrashes after the user credentials are asked for.
It doesn’t matter if the credential are valid or not.
There was a serious security vulnerability with SMB, the protocol Windows uses to mount network shares like this. The flaw was fixed on the Linux side and in later versions of Windows. Perhaps, since Win 7 is end of life, it never got fixed and now Win 7 is no longer able to work with Linux samba shares. Just a guess, I have no idea if that would be the case.