El Capitan 10.11.5 update SMB slow (bug)

Quick update.

1. Rather than mess with anything on the server side, I went ahead and just created a nsmb.conf file in /etc with vim. Mine didn't exist yet. sudo is required. It's as simple as just writing into the file:

   [default]
   
       client_signing=no

2. Restarting the OS X 10.11.5 client.

I'm happy to report that everything's working fine now! 🙂

A few notes:

• There's a man page for nsmb.conf included in OS X, which details this flag.
• When this nsmb.conf file is in /etc, and you put the flag in the [default] section, the settings are global for the whole boot disk. This will override any user-specific nsmb.conf you might have in the ~/Library/Preferences/nsmb.conf, if it exists for your user account.
• My NAS is on an offline LAN, so I don't really need the added security of SMB signing. If your NAS is connected to the Internet, you may want to keep signing on, even at the cost of poor performance, or you may want to adjust your workflow so that your high-speed SMB shares are offline, safe, and don't require SMB signing, while you use SMB with signing to access your server online to protect against those man in the middle or Badlock attacks.

On a related note, one of the Samba developers had a guess as to why Apple might have changed the defaults with such drastic performance implications, and without notice: http://article.gmane.org/gmane.network.samba.general/157447

Thanks for posting... very helpful. Not sure what Apple can do to fix that, but we shall see.

Seth Goldin wrote:

Quick update.

1. Rather than mess with anything on the server side, I went ahead and just created a nsmb.conf file in /etc with vim. Mine didn't exist yet. sudois required. It's as simple as just writing into the file:
   1. [default]
   2. 
      
   3. client_signing=no
2. Restarting the OS X 10.11.5 client.

I'm happy to report that everything's working fine now! 🙂

A few notes:

• There's a man page for nsmb.conf included in OS X, which details this flag.
• When this nsmb.conf file is in /etc, and you put the flag in the [default] section, the settings are global for the whole boot disk. This will override any user-specific nsmb.conf you might have in the ~/Library/Preferences/nsmb.conf, if it exists for your user account.
• My NAS is on an offline LAN, so I don't really need the added security of SMB signing. If your NAS is connected to the Internet, you may want to keep signing on, even at the cost of poor performance, or you may want to adjust your workflow so that your high-speed SMB shares are offline, safe, and don't require SMB signing, while you use SMB with signing to access your server online to protect against those man in the middle or Badlock attacks.

Oops, I was looking at the server's man page when I wrote this. The actual flag in the client's nsmb.conf is `signing_required=no`. Sorry if I confused anyone.

The trick didn't work for me. Created as you explained the nsmb.conf file, rebooted, Finder mount fairly rapidly the volume but then finder still takes years to open folders and files. ******.

Edit: it works indeed better with signing|required. I made the confusion as well. Finder now opens folders and files the right speed ;-))

Patrick Merel1 wrote:

The trick didn't work for me. Created as you explained the nsmb.conf file, rebooted, Finder mount fairly rapidly the volume but then finder still takes years to open folders and files. ******.

Finder -> View -> Show View Options -> [_] Show icon preview (turn this off) for your SMB volume and folders

thanxx bob, it may help as well.

Really wished this worked for me but adding the nsmb.conf and making the change to the plist had no effect when connecting to my Synology DS413. Rebooted the Mac and the NAS and still got the spinning wheel anytime I opened a folder from the NAS through finder. Accessing it using afp:// or nfs:// works fine. Maybe my issue is specific to Synology devices? Not sure what else there is to try.

take care, this is not a plist file. I have used pathfinder to open the /etc invisible folder. I have selected a .conf file and duplicated it. I opened it with textedit, deleted the content, modified as explained by Seth and renamed it nsmb.conf Done. After reboot, the trick made it.

Thank you so much Bob! This worked perfectly for me. I'm all up and running again after a frustrating few days trying to solve this. Thanks once again. 😍

Patrick Merel1 wrote:

take care, this is not a plist file. I have used pathfinder to open the /etc invisible folder. I have selected a .conf file and duplicated it. I opened it with textedit, deleted the content, modified as explained by Seth and renamed it nsmb.conf Done. After reboot, the trick made it.

I meant in addition to creating the nsmb.conf I also edited com.apple.smb.server.plist as referenced here. Re: iOS File Share apps unable to access File Shares since 10.11.5. Neither has worked for me.

That's worked for me too. Many thanks for this great support, bro !

I am having this issue and it is really annoying for me. I raised a case with Apple support, and during troubleshooting it is working when root account is enabled and logged in with that. I was asked to re-install a fresh OS and test if a standard admin / guest accounts will work after that. I am reluctant as I am, not really convinced that OS Reinstallation will fix it.

anyhow, I will need to follow these steps. if I manage to get any solution in between are after I will share here.

Thank you !! That solved my problem.. I couldn't connect to a windows drive via SMB as I used to before after updating to 10.11.5 !!

My Drobo 5N has this same problem. I had been using it while editing video with FCP-X but now it is unusable; the read rate has gone to about 1/6 of what it had been. Thank you Apple...