I have the same problem, at least in part, but it only took force on my last system upgrade - on the 2nd Feb 2019.
Now I cannot access other Linux Mint machines, or a newly built LXDE 3 machine, that is also unable to access most external shares.
I can still access a Raspberry Pi 2 running Raspbian, and my QNAP NAS.
It may be related that I can no longer access my email form and independent mail provider (Alpha.net.au), Gmail and Hotmail accounts from Thunderbird, but I can still access my email from my ISP. I can access all three of those accounts via browser access.
Thank you in advance for any help.
-----------------------------
Sysinfo
-----------------------------
System information report, generated by Sysinfo: 3/02/2019 9:26:33 PM
http://sourceforge.net/projects/gsysinfo
SYSTEM INFORMATION
Running LinuxMint Linux, the LinuxMint 19.1 (tessa) release.
GNOME: 3.28.2 (Ubuntu)
Kernel version: 4.18.0-14-generic (#15~18.04.1-Ubuntu SMP Mon Jan 14 11:09:26 UTC 2019)
GCC: 7 (x86_64-linux-gnu)
Xorg: 1.19.6 (25 October 2018 04:11:27PM) (25 October 2018 04:11:27PM)
Hostname: csirac
Uptime: 0 days 8 h 53 min
CPU INFORMATION
AuthenticAMD, AMD FX(tm)-8350 Eight-Core Processor
Number of CPUs: 8
CPU clock currently at 1404.025 MHz with 2048 KB cache
Numbering: family(21) model(2) stepping(0)
Bogomips: 8027.27
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl nonstop_tsc cpuid extd_apicid aperfmperf pni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 popcnt aes xsave avx f16c lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs xop skinit wdt fma4 tce nodeid_msr tbm topoext perfctr_core perfctr_nb cpb hw_pstate ssbd ibpb vmmcall bmi1 arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold
MEMORY INFORMATION
Total memory: 32068 MB
Total swap: 34263 MB
STORAGE INFORMATION
SCSI device - scsi0
Vendor: ATA
Model: Samsung SSD 860
SCSI device - scsi1
Vendor: ATA
Model: Samsung SSD 840
SCSI device - scsi2
Vendor: ATA
Model: WDC WD60EZRZ-00R
SCSI device - scsi3
Vendor: ATA
Model: ST12000VN0007-2G
HARDWARE INFORMATION
MOTHERBOARD
Host bridge
Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 5
Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] RD9x0/RX980 Host Bridge
PCI bridge(s)
Advanced Micro Devices, Inc. [AMD/ATI] RD890/RD9x0/RX980 PCI to PCI bridge (PCI Express GFX port 0) (prog-if 00 [Normal decode])
Advanced Micro Devices, Inc. [AMD/ATI] RD890/RD9x0/RX980 PCI to PCI bridge (PCI Express GPP Port 0) (prog-if 00 [Normal decode])
Advanced Micro Devices, Inc. [AMD/ATI] RD890/RD990 PCI to PCI bridge (PCI Express GFX2 port 0) (prog-if 00 [Normal decode])
Advanced Micro Devices, Inc. [AMD/ATI] RD890/RD9x0/RX980 PCI to PCI bridge (PCI Express GPP2 Port 0) (prog-if 00 [Normal decode])
Advanced Micro Devices, Inc. [AMD/ATI] SBx00 PCI to PCI Bridge (rev 40) (prog-if 01 [Subtractive decode])
Advanced Micro Devices, Inc. [AMD/ATI] SB700/SB800/SB900 PCI to PCI bridge (PCIE port 0) (prog-if 00 [Normal decode])
Advanced Micro Devices, Inc. [AMD/ATI] SB700/SB800/SB900 PCI to PCI bridge (PCIE port 1) (prog-if 00 [Normal decode])
Advanced Micro Devices, Inc. [AMD/ATI] SB900 PCI to PCI bridge (PCIE port 2) (prog-if 00 [Normal decode])
Advanced Micro Devices, Inc. [AMD/ATI] SB900 PCI to PCI bridge (PCIE port 3) (prog-if 00 [Normal decode])
Advanced Micro Devices, Inc. [AMD] Device 1470 (rev c1) (prog-if 00 [Normal decode])
Advanced Micro Devices, Inc. [AMD] Device 1471 (prog-if 00 [Normal decode])
ISA bridge
Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 LPC host controller (rev 40)
Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 LPC host controller
GRAPHIC CARD
VGA controller
Advanced Micro Devices, Inc. [AMD/ATI] Vega [Radeon RX Vega] (rev c1) (prog-if 00 [VGA controller])
Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] Vega 10 XT [Radeon RX Vega 64]
SOUND CARD
Multimedia controller
Advanced Micro Devices, Inc. [AMD/ATI] Device aaf8
Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] Device aaf8
NETWORK
Ethernet controller
Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 09)
Subsystem: ASUSTeK Computer Inc. P8 series motherboard
-----------------------------
smb.conf
-----------------------------
#
# Sample configuration file for the Samba suite for Debian GNU/Linux.
#
#
# This is the main Samba configuration file. You should read the
# smb.conf(5) manual page in order to understand the options listed
# here. Samba has a huge number of configurable options most of which
# are not shown in this example
#
# Some options that are often worth tuning have been included as
# commented-out examples in this file.
# - When such options are commented with ";", the proposed setting
# differs from the default Samba behaviour
# - When commented with "#", the proposed setting is the default
# behaviour of Samba but the option is considered important
# enough to be mentioned here
#
# NOTE: Whenever you modify this file you should run the command
# "testparm" to check that you have not made any basic syntactic
# errors.
#======================= Global Settings =======================
[global]
## Browsing/Identification ###
# Change this to the workgroup/NT-domain name your Samba server will part of
workgroup = WORKGROUP
client ntlmv2 auth = no
client use spnego = no
client lanman auth = yes
client ipc signing = disabled
encrypt passwords = no
# server string is the equivalent of the NT Description field
server string = %h server (Samba, Ubuntu)
# Windows Internet Name Serving Support Section:
# WINS Support - Tells the NMBD component of Samba to enable its WINS Server
# wins support = no
# WINS Server - Tells the NMBD components of Samba to be a WINS Client
# Note: Samba can be either a WINS Server, or a WINS Client, but NOT both
; wins server = w.x.y.z
# This will prevent nmbd to search for NetBIOS names through DNS.
dns proxy = no
#### Networking ####
# The specific set of interfaces / networks to bind to
# This can be either the interface name or an IP address/netmask;
# interface names are normally preferred
; interfaces = 127.0.0.0/8 eth0
# Only bind to the named interfaces and/or networks; you must use the
# 'interfaces' option above to use this.
# It is recommended that you enable this feature if your Samba machine is
# not protected by a firewall or is a firewall itself. However, this
# option cannot handle dynamic or non-broadcast interfaces correctly.
; bind interfaces only = yes
#### Debugging/Accounting ####
# This tells Samba to use a separate log file for each machine
# that connects
log file = /var/log/samba/log.%m
# Cap the size of the individual log files (in KiB).
max log size = 1000
# If you want Samba to only log through syslog then set the following
# parameter to 'yes'.
# syslog only = no
# We want Samba to log a minimum amount of information to syslog. Everything
# should go to /var/log/samba/log.{smbd,nmbd} instead. If you want to log
# through syslog you should set the following parameter to something higher.
syslog = 0
# Do something sensible when Samba crashes: mail the admin a backtrace
panic action = /usr/share/samba/panic-action %d
####### Authentication #######
# Server role. Defines in which mode Samba will operate. Possible
# values are "standalone server", "member server", "classic primary
# domain controller", "classic backup domain controller", "active
# directory domain controller".
#
# Most people will want "standalone sever" or "member server".
# Running as "active directory domain controller" will require first
# running "samba-tool domain provision" to wipe databases and create a
# new domain.
server role = standalone server
# If you are using encrypted passwords, Samba will need to know what
# password database type you are using.
passdb backend = tdbsam
obey pam restrictions = yes
# This boolean parameter controls whether Samba attempts to sync the Unix
# password with the SMB password when the encrypted SMB password in the
# passdb is changed.
unix password sync = yes
# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan <<
kahan@informatik.tu-muenchen.de> for
# sending the correct chat script for the passwd program in Debian Sarge).
passwd program = /usr/bin/passwd %u
passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
# This boolean controls whether PAM will be used for password changes
# when requested by an SMB client instead of the program listed in
# 'passwd program'. The default is 'no'.
pam password change = yes
# This option controls how unsuccessful authentication attempts are mapped
# to anonymous connections
map to guest = bad user
########## Domains ###########
#
# The following settings only takes effect if 'server role = primary
# classic domain controller', 'server role = backup domain controller'
# or 'domain logons' is set
#
# It specifies the location of the user's
# profile directory from the client point of view) The following
# required a [profiles] share to be setup on the samba server (see
# below)
; logon path = \\%N\profiles\%U
# Another common choice is storing the profile in the user's home directory
# (this is Samba's default)
# logon path = \\%N\%U\profile
# The following setting only takes effect if 'domain logons' is set
# It specifies the location of a user's home directory (from the client
# point of view)
; logon drive = H:
# logon home = \\%N\%U
# The following setting only takes effect if 'domain logons' is set
# It specifies the script to run during logon. The script must be stored
# in the [netlogon] share
# NOTE: Must be store in 'DOS' file format convention
; logon script = logon.cmd
# This allows Unix users to be created on the domain controller via the SAMR
# RPC pipe. The example command creates a user account with a disabled Unix
# password; please adapt to your needs
; add user script = /usr/sbin/adduser --quiet --disabled-password --gecos "" %u
# This allows machine accounts to be created on the domain controller via the
# SAMR RPC pipe.
# The following assumes a "machines" group exists on the system
; add machine script = /usr/sbin/useradd -g machines -c "%u machine account" -d /var/lib/samba -s /bin/false %u
# This allows Unix groups to be created on the domain controller via the SAMR
# RPC pipe.
; add group script = /usr/sbin/addgroup --force-badname %g
############ Misc ############
# Using the following line enables you to customise your configuration
# on a per machine basis. The %m gets replaced with the netbios name
# of the machine that is connecting
; include = /home/samba/etc/smb.conf.%m
# Some defaults for winbind (make sure you're not using the ranges
# for something else.)
; idmap uid = 10000-20000
; idmap gid = 10000-20000
; template shell = /bin/bash
# Setup usershare options to enable non-root users to share folders
# with the net usershare command.
# Maximum number of usershare. 0 (default) means that usershare is disabled.
; usershare max shares = 100
# Allow users who've been granted usershare privileges to create
# public shares, not just authenticated ones
usershare allow guests = yes
#======================= Share Definitions =======================
# Un-comment the following (and tweak the other settings below to suit)
# to enable the default home directory shares. This will share each
# user's home directory as \\server\username
;[homes]
; comment = Home Directories
browseable = yes
# By default, the home directories are exported read-only. Change the
# next parameter to 'no' if you want to be able to write to them.
; read only = yes
# File creation mask is set to 0700 for security reasons. If you want to
# create files with group=rw permissions, set next parameter to 0775.
; create mask = 0700
# Directory creation mask is set to 0700 for security reasons. If you want to
# create dirs. with group=rw permissions, set next parameter to 0775.
; directory mask = 0700
# By default, \\server\username shares can be connected to by anyone
# with access to the samba server.
# Un-comment the following parameter to make sure that only "username"
# can connect to \\server\username
# This might need tweaking when using external authentication schemes
; valid users = %S
# Un-comment the following and create the netlogon directory for Domain Logons
# (you need to configure Samba to act as a domain controller too.)
;[netlogon]
; comment = Network Logon Service
; path = /home/samba/netlogon
; guest ok = yes
; read only = yes
# Un-comment the following and create the profiles directory to store
# users profiles (see the "logon path" option above)
# (you need to configure Samba to act as a domain controller too.)
# The path below should be writable by all users so that their
# profile directory may be created the first time they log on
;[profiles]
; comment = Users profiles
; path = /home/samba/profiles
; guest ok = no
; browseable = no
; create mask = 0600
; directory mask = 0700
[transfer]
comment = Transfer directory
path = /home/jcp/Public/transfer
writeable = yes
browseable = yes
valid users = jcp
[printers]
comment = All Printers
browseable = no
path = /var/spool/samba
printable = yes
guest ok = no
read only = yes
create mask = 0700
# Windows clients look for this share name as a source of downloadable
# printer drivers
[print$]
comment = Printer Drivers
path = /var/lib/samba/printers
browseable = yes
read only = yes
guest ok = no
# Uncomment to allow remote administration of Windows print drivers.
# You may need to replace 'lpadmin' with the name of the group your
# admin users are members of.
# Please note that you also need to set appropriate Unix permissions
# to the drivers directory for these users to have write rights in it
; write list = root, @lpadmin
For the past few weeks, I've been banging my head against the wall trying to see folders in my Mint PC from my Win7 PC. So far, it's been only a 1-way street. I can see my Win7 folders from Mint by entering command line such as, "smb://dad-win7-pro/downloads/" in the loaction field in File Manager. I know even that's still a workaround (and not correct) because you'd typically see folder icons in a directory like in a typical OS. I don't want to type everytime to access a folder.
Tried numerous times but still no go. Posting following commands suggested by altair4 so you can see how I'm set up. Hopefully I'm providing this info correctly. Please bear with me if I'm not. If you need more info from me, let me know. Thanks for all your help in advance. 
Please reply. Thanks.
John.