Thank you @CasperSally - Not sure how I could have possibly missed this behavior since 10.12.2! Weird...

@KSchroeder No, the /etc/nsmb.conf file doesnt not exisit unless something (or someone) generates it. I belive it's a FreeBSD config file specific to SMB/CIFS clients (i.e.; not servers).

My nsmb.conf file is failry simple:

[default]
streams=yes
file_ids_off=yes
signing_required=no

(I manage it with an Jamf extension attribute along with a policy/script that generates the config file on newly-deployed systems (and any system that is missing the file for some reason)

There a a lot of switches that can be tweaked to optimize SMB sessions/mounts in the nsmb.conf file. Failry granular.

I have used /etc/nsmb.conf hand-in-hand with /etc/sysctl.conf to fine-tune my Macs for my EMC/Isilon file servers.

type man nsmb.conf and man sysctl.conf for the juicy details.

Editing nsmb.conf worked perfectly for me. Thanks!

Anyone getting account lockout with this issue also?

@redwings, the 10.12.6 Beta (16G23a) update appears to have fixed the problem for us.

@MaryDuffy Thanks! I'll give it a go!

@MaryDuffy Thanks! I'll give it a go!

Took me forever to find a solution(strangely Google/searching JAMF did not bring this back as a result... but plenty of results from 2012...)

thanks for the info

@Key1 We've been having some issues with login times after sleep/re-opening the macbook lid.. Unsure if it's related. I can't consistently recreate the issue, on my mac minimally. However we have some VIPs that are complaining and swearing it's happening to them consistently..

As of today's release of the 10.12.6 update. I downloaded and upgraded my first test machine. My machine that has been plagued by not being able to mount SMB shares. It seems to be working normally again with the 10.12.6 update.

Thanks to annamentzer. Her work around helped me get by till today.

Just thought I'd share.

@annamentzer - running the command worked for a couple of users we've tested so far.
@dstranathan - unfortunately creating that file didn't work initially, had to run the suggested command to get the SMB shares to mount.

pkill -9 AppleIDAuthAgent

Seems to be limited to pre-existing 10.12.5 user profiles as well. New users did not appear to be affected with mounting SMB shares or connecting to network printers.

One client also isn't executing any login / logout hooks, in fact no Casper policies set to run at logon, with any frequency (e.g. Ongoing). We can manually get the policies to run though (e.g. sudo jamf recon, or sudo jamf policy -event login). Not sure if this is related at this stage. Looking at a re-image for this particular iMac.

A complete image with 10.12.5 also did not present the problem for us (obviously not an ideal with active clients).

We use AD in our environment - curious to note that on local user profiles the "OUR-DOMAIN/Domain Users" Network Group has read permission. Is this also new?

Using a Casper policy to execute the script on login as a temporary band-aid. Watching with interest for the final release of 10.12.6!

@dstranathan

Would you be willing to share some of your process of using sysctl.conf for managing EMC/Isilon shares? I have been running into some real headaches with our Isilon shares here and would love to give this a try.

Thanks!

I think currently we are setting this on 10.12 Sierra clients:

net.inet.tcp.delayed_ack=0

But our settings have changed over the years based on the version/type of EMC/Isilon gear we were running as well as the version of MacOS (and version of SMB/NFS too, of course). EMC publishes client recomendations in a best practice PDF guide from time to time. Example: "Using Mac OS X with Isilon OneFS Sept 2014"). Your EMC rep/support team should be able to make recomendations and send you the PDF.

sudo sh -c "echo '[default]' >> /etc/nsmb.conf; echo 'protocol_vers_map=1' >> /etc/nsmb.conf"

This worked for us.