network-manager update breaks internet

[Mick]

Clean install of Mint 18.1 Serena 64 bit. Network access OK, internet access OK.
Run Update Manager - apply updates and I can no longer access the internet. I can ping devices on my local network and open web pages on my local network, but cannot ping or load anything outside my network.
Repeat with a new clean install - apply all updates except network-manager and everything is fine.

The problem first appeared on my Mint 18 Cinnamon system, many clean installs to try to understand and fix the problem.

This is reproducible.

This bug renders the machine pretty much useless and so it is important that it gets fixed quickly.

[Mick (mick-sulley)]

This problem affected both my desktop and laptop, both Mint 18 at the time. All of the re-installs I did on desktop, my laptop still had the problem. I just ran -

sudo apt-get install network-manager=1.2.2-0ubuntu0.16.04.4

power cycled, and it is running fine again.

[Mick (mick-sulley)]

More detailed investigation -

18.1 ==========================================
Downloaded and installed Mint Cinnamon 18.1 64 bit
ping and web page access working as expected
Updates available - set to 'Optimise stability and security'
install mintupdate and mint-upgrade-info
now 113 updates available - install all except network-manager
shutdown and restart
ping and web page access still working as expected

Install kernels
4.4.0-81.104
4.8.0-46
4.10.0-20

mick@Mint18 ~ $ dpkg -l network-manager
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-=========================================-=========================-=========================-========================================================================================
ii network-manager 1.2.2-0ubuntu0.16.04.3 amd64 network management framework (daemon and userspace tools)

Update available - network-manager to version 1.2.6-0ubuntu0.16.04.1
install the update

mick@Mint18 ~ $ dpkg -l network-manager
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-=========================================-=========================-=========================-========================================================================================
ii network-manager 1.2.6-0ubuntu0.16.04.1 amd64 network management framework (daemon and userspace tools)

ping and web page access still working as expected

shutdown and restart

mick@Mint18 ~ $ ping bbc.co.uk
ping: unknown host bbc.co.uk

browser bbc.co.uk - server not found

shutdown and restart in 4.8 kernel - problem still there and again into 4.10 kernel and the problem is still there.

sudo apt-cache showpkg network-manager
lists
1.2.6-0ubuntu0.16.04.1 -
1.2.2-0ubuntu0.16.04.4 -
1.1.93-0ubuntu4 -

mick@Mint18 ~ $ sudo apt-get install network-manager=1.2.2-0ubuntu0.16.04.4
failed resolving the source. Tried several times but always failed.
This definitely worked on my laptop, and it has worked on desktop on at least one occasion but will not work now.

18.2 =================================
Downloaded Mint 8.2 Cinnamon 64 bit Beta and installed.
Problem as before
mick@Mint18-2 ~ $ ping bbc.co.uk
ping: unknown host bbc.co.uk
mick@Mint18-2 ~ $ ping 212.58.244.27
    works fine
mick@Mint18-2 ~ $ sudo apt-cache showpkg network-manager
1.2.6-0ubuntu0.16.04.1 -
1.1.93-0ubuntu4 -

mick@Mint18-2 ~ $ sudo apt-get install network-manager=1.1.93-0ubuntu4
had to try this twice - first time
  Temporary failure resolving 'archive.ubuntu.com'
second time it worked

still cannot ping bbc.co.uk

restart

Message box
unable to launch "cinnamon-session-cinnamon" X session ---
"cinnamon-se...