Copying files from MacBook Pro (MBP) to EX2 crashes Mac


I have an EX2 setup on our LAN as a TIme Machine backup and for centralized storage. A few days ago, I was copying files from the MBP to a piblic share on the EX2 and the MBP crashed hard. I had the MBP hard drive wiped, reinstalled OS X and created a test account. I can recreate the crashes at will by copying files from the computer to the EX2. Has anyone experienced this?

MBP: Mid-2012, Yosemite 10.10.1

WD NAS EX2: latest firmware, 6TB

v/r bill

  1. IS your WD EX2 connect to a router via a CAT5e or CAT6 cable?

2a. If your MBP hardwired or wireless connect?

2b. If your MBP is wireless, is it on a 2.4GHz band or 5GHz band?

  1. How are you copying the files over and do you have permissions set on the WD EX2 shares appropritately?

  2. What kind of files you coping over?

thanks for the response!

1.  router is connected via cat5

2.a. when backing up those files, connected wired

3 finder copies to my share on the WD EX2, so permissions ok

  1. all kinds of files will fail, including movies, music, MS Office documents, etc

Problems do NOT occur with the other 3 Macs in the house using the EX2…

Further troubleshooting leads us to conclude that the Mac’s hard drive is fine but the hard drive SATA CABLE may be bad.  System seems to work fine from an external boot disk.  Random application freezes (such as the Finder freezing when copying files) and unresponsive cursor are symptoms of a bad cable reported by many people.  Definitive solution is to put the HD in an external enclosure and see if it freezes. If it works fine, then its the cable.


Could be the laptop itself


I recommend any/all devices that can/are hardwired to be using Cat5e at minimum. Even connect the router to the modem via CAT5e or better.

  • CAT5 - Cat 5 is the slowpoke of the bunch. It can handle 10/100 Mbps speeds (Fast Ethernet) at up to 100 MHz bandwidth
  • CAT5e (Enhanced) - A step above Cat 5, it can handle 1000 Mbps speeds (gigabit Ethernet) at 100 MHz.
  • CAT6 - Category 6 is a major improvement over Cat 5e. It’s really just the bee’s knees. It’s suitable for up to 10 gigabit Ethernet at 250 MHz.

How are all the OTHER MACs connected to your network?

Even more troubleshooting has apparently resolved the problem. All of the problems are symptoms of a user with read only permissions to their account. How that happened I have no idea! I was able to reset permissions and ACL to the account owner and everything seems to be working well.  The problems were intermittent but haven’t reappear in 24 hours.

Thanks for the information.  Our cabling was state of the art when we built in the structured wiring in 2005, and its really impractical to rewire the cat5 to cat5e ocr cat6.

All of my patch cables are cat5e or cat6. I buy them from Monoprice.


Glad you got it resolved.

Turns out permissions was a symptom of the problem, not the problem itself. The problem was the hard drive bracket (cable) was bad. Apparently this is a common problem with Macbook Pros. Apple replaced the cable the computer is working perfectly.