Network Issues when using SMB on Mac OSX

SMB support from Apple is still a work in progress, certain network setups could still have some potential issues. SMB on Mac OS has been a moving target, but it is getting better. It is more mature with Mac OS 10.10 and 10.11. 

Some background information on SMB 

SMB is Microsoft’s proprietary network file sharing protocol. Most versions of OS X prior to 10.7 relied on an open-source implementation of SMB called Samba for accessing Windows file shares and sharing files with Windows clients. When the licensing terms for Samba changed, Apple had to develop their own SMB implementation. Apple has been struggling with it and it is still not as stable as it should be. 

Possible Issues 

• We have not seen any issues with SMB on Windows clients. 
• On Mac OS X, we have seen ACL permissions problems with SMB2 and SMB3 with certain versions of OS X (early 10.9.x). 
• We have not seen the same issues with AFP or SMB1 (“CIFS” protocol prefix). 
• Many SMB issues are related to a mix of SMB protocols between clients. 
• SMB3 (now the default for Mac OS 10.10) could have problems when interworking with machines that don’t have full support for SMB3. 
• Much better results can be expected when all machines where on the same SMB protocol version. 

Our recommendations are: 

• Use client native support when possible 
• AFP on Mac OS and SMB on Windows 
• If you must use SMB, use the latest version of the protocol if possible (currently SMB3). 
• Use the same SMB version for all clients. 
• Use the newest OS X version. 

Following these recommendations should provide a better experience. 

We are all hopeful that Apple will improve the stability of the its SMB protocol at a faster pace now that they have made it the default protocol for Mac OS.