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Mac OS X 10.10 Yosemite File Sharing SMB Super Slow

Guys, whatever you do — don’t upgrade your 10.9 servers to a 10.10 — unless you don’t mind waiting a few minutes to open up a file share.

According to Apple’s site, Mac OS X 10.10 Yosemite runs a new SMB version 3, which is suppose to be “faster/better”, yada yada. Turns out, since 10.6, theres been many many issues with Macs and Windows machines trying to access file services via SMB or AFP. I ran into this situation first hand.


As a matter of fact, a quick google search resulted in me finding this 8 page thread on all the horrors of Mac users trying to get their file server working properly. Some fixes include reverting your Mac to run SMB version 1 by editing nsmb.conf file or by downloading this app called SMBconfig.

echo "[default]" >> ~/Library/Preferences/nsmb.conf; echo "smb_neg=smb1_only" >> ~/Library/Preferences/nsmb.conf

rm ~/Library/Preferences/nsmb.conf

Use the line aboe to remove the change we did — thanks to Mac Hints for this.

If all else fails, you’ll need to downgrade or move the file services to a different machine that isnt running Mac OS X 10.10. Mac OS X 10.9 worked fine for me.


Theres a guide off Mac World on how to do this, but at the end of the day, its just best to steer clear of 10.10!

Major face plam, Apple, Major face palm. And here I thought Macs “just worked”….not the case here. Leave the networking to the pros, Apple –  apparently networking is not your forte.




William Zambrano

William Zambrano

NYC networkers is run by William Zambrano, a passionate network engineer who has been in the IT industry for eight years who posts up blog articles, YouTube videos, and holds meetup.com events in the NYC area. He lives in Queens, New York and has consulted in various different companies in the NY area. Previously William worked as a Cisco Certified Systems Instructor (CCSI) but now currently works for Arista Networks serving as a Systems Engineer. William can be reached by email at willzambrano@gmail.com

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  1. Well, to be honest, I’ve had same issue with Osx 10.9, 10.8 and 10.7

    As far as I know, it happens after upgrade from 10.6 to 10.7. OsX 10.6 (Snow Leopard) worked with SMB 1 protocol, after updating to SMB 2 in Lion, and even now with SMB 3 in Yosemite, each time you try to connect to a SMB share in, for example, Windows 2003, its performance is awful.

    If fact, I have same W2003 file server since I work with 10.6, we connect Apple and Linux computers, all of them via SMB protocol, and Linux performance is as good as always, but OsX performance is a nightmare…

    Anyway it’s to be something else, cause I have forced OsX to work only via SMB1, and even when performance is better, it is not as good as it’s in Linux or it was in 10.6.

    Why Apple doesn’t say anyting…???

  2. Not sure if this still is an issue or not, but I have had similar issues with Mac computers connecting to windows servers.

    What I did was change some settings on the mac clients. I edited /etc/sysctl.conf and added the following lines to it:


    Hope this helps.

  3. I’ve never understood the Apple hype. My gf wanted this Macbook… good thing we didn’t pay $1,500 for this mediocre computer which can’t even access shared drives.. o wait, we did pay that much for this piece of crap. At least it’s pretty.

    • William Zambrano

      Alex, I’m with you on that! Apple is made for the general workgroup space, not really mean’t for a corporate setting (hence their Open Directory isn’t on par with M$’s Active Directory). Then again I haven’t kept up with Apple’s tools in the past few years but thats always been my findings.



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