Mac Pro Late 2013 USB problems / freezing
I have a quad-core CPU Mac Pro late 2013 (Model Identifier: MacPro6,1). MacOS X 10.9.5.
I have had all sorts of USB devices hooked up to it. At any one time, I usually have all 4 ports filled. I have a 3TB USB 3.0 disk that stores my large files, a USB mouse and keyboard (logitech with a usb mini dongle), a cable to charge my logitech USB cordless mouse, Lightning cable to my iPhone 5, and other things that I rotate in and out, like CF card reader, Audio Box USB audio interface from PreSonus, Sony Webcam, etc.
About 3 months into having the Mac Pro, I noticed that my keyboard went dead in the middle of using it. The mouse was dead too. I blamed the RF dongle that they both share, because the Apple Magic Trackpad (bluetooth) I have still functioned. Try as I might, I couldn't get the keyboard or mouse to work again, so I used the Magic Trackpad to restart the machine, and then my keyboard and mouse worked again.
It wasn't until later that I realized that all the USB busses on the machine had frozen or "died" temporarily. I realized it later because my USB hard drive complained about being "ejected improperly."
Now I have had the USB die on the Mac Pro at least 15 times over the last month and a half. Usually once every two days or so.
I have tried (almost one by one) using some of the USB devices on the mac, and removing others to ascertain if it's a certain USB device that is causing this. But the odd thing is that I never get a message from the OS like "xxx USB device is drawing too much power."
I'm going a little nuts here because I cannot see any rhyme or reason to the USB interface lock ups. And each time it happens, all the USB devices go dead until I restart. Sometimes, I'm able to SSH into the machine from my iPhone and issue a "shutdown -h now" and even though I see the Mac OS X UI shutdown, it never fully halts. I often have to hold the power button to get the machine to turn off.
I really can't say if it's software related, hardware related or what. I've tried to watch my workflow carefully to see if anything seems to make a pattern, but nothing yet.
Any suggestions? Is anyone else seeing behavior like this? Do we think it's a USB device... or is my Mac Pro flakey?
Thanks!
OS X Mavericks (10.9.3), Accessibility