brycesteiner
Level 1 (25 points)
Mac OS X

Q: File Server to Windows Fails after security update

I just upgraded to the security update that came out last week and suddenly the windows computers cannot access the server. I'm running 10.11.6 and everything had been great until we started the windows computers up today. They can ping and access the internet but they cannot access SMB on the server.

The Macs have no issues connecting in both SMB and AFP.

Any ideas what changed? The users in Server are all still there and it looks like it should work. I can access the servers web page too.

Mac mini, OS X El Capitan (10.11.2), 2011 Mac Mini Server

Posted on Sep 6, 2016 7:34 AM

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brycesteiner

Q: File Server to Windows Fails after security update

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  • by fkick1,Helpful

    fkick1 fkick1 Sep 6, 2016 5:08 PM in response to brycesteiner
    Level 1 (73 points)
    Servers Enterprise
    Sep 6, 2016 5:08 PM in response to brycesteiner

    Make sure that you're including the domain in the username when signing in. i.e. USER: WORKGROUP\username

     

    Also check that your windows machine has the correct LM Compatbility level set. For El Cap servers it needs to be set to 3.

     

    Follow the instructions below to change the Windows security settings to allow SMB connections on Windows.

    1. Click the Start button , and in the search bar at the bottom, type in regedit . Select regedit from the search results and the registry will open.
    2. Using the folders on the left of the screen, navigate the tree to the following location: \HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
    3. In the window at the right, look for the following DWORD: LmCompatibilityLevel . If it exists, double click on it and set its value to 3 (in decimal).  If it does not exist, right-click in some empty space in the right side of the window and create a new DWORD called LmCompatibilityLevel and set it's value to 3 (in decimal).
    4. Restart the computer.
    5. Re-attempt to connect to the  server through My Computer.

     

    NOTE: Home versions of windows may not have the ability to set the LM level, and unfortunately I haven't found a way around that.

  • by brycesteiner,

    brycesteiner brycesteiner Sep 6, 2016 5:12 PM in response to fkick1
    Level 1 (25 points)
    Mac OS X
    Sep 6, 2016 5:12 PM in response to fkick1

    I did try the login that way (I actually have it set to auto login with mapped drives on all the windows computers but none would work today).

    I will double check the other things when I get to work tomorrow. Strange how this happened so suddenly after I updated the server on Saturday.

    Thanks!