MathWorks is aware of a bug in MATLAB R2014a, R2014b, and R2015a related to MATLAB's licensing components which can affect the Mac Pro (2013+). This issue has been reported to the vendor (Flexera Software) responsible for MATLAB's licensing components. Many hardware configurations are affected, but a Mac Pro (2013) with two Thunderbolt Displays connected is particularly susceptible to this bug.
The bug will manifest itself on any hardware configuration where "ifconfig" reports more than ten "en" (Ethernet) interfaces. Since Thunderbolt Displays contain multiple network interfaces, connecting more than two of them to a Mac Pro (2013) will cause the Ethernet interface count to rise above ten. The Mac Pro (2013+) has nine built-in Ethernet interfaces, and Thunderbolt Displays contain an additional Ethernet interface which therefore increases the total Ethernet network interface count by one when a Thunderbolt display is connected.
To confirm whether a Mac is susceptible to this bug, launch the Terminal application and enter "ifconfig" at the prompt. A series of network interfaces will be listed. If the number of entries starting with "en" is greater than ten, then the Mac is susceptible.
This bug was resolved in MATLAB R2015b.
Workaround 1: Update to R2015b or later (Recommended)
This bug was fixed in MATLAB R2015b. The simplest way to resolve this issue is to update to R2015b or later.
*Workaround 2: Disconnect Extra Displays *
Disconnect devices from your Mac which add additional Ethernet network interfaces to reduce the total Ethernet interface count to ten or less. If you have multiple Thunderbolt Displays, disconnecting all but one of them is the quickest way to bring the count back down to ten.
When applying this workaround, devices disconnected cannot be reconnected while MATLAB is running. Doing so can cause the error to occur.
Workaround 3: Disable Thunderbolt Networking (Advanced Users)
NOTE: If you are not familiar with Terminal, please consult your IT department or use the recommended workaround listed above.
As an alternative workaround, you may run a command listed below, which will reduce the number of Ethernet interfaces until the next reboot by disabling IP-over-Thunderbolt functionality which most users do not need.
This will not unload your Ethernet or Wi-Fi interfaces, even those on your Thunderbolt Displays. This does not impact any other functionality of Thunderbolt. If you need to use these interfaces after unloading them, this is possible with another terminal command, or you can simply restart your Mac.
These devices must remain unloaded during your MATLAB session. If you decide to reload them, your MATLAB session may crash.
To unload the IP-over-Thunderbolt network interface, run the following command in Terminal (this command must be run each time your Mac restarts):
sudo kextunload -v /System/Library/Extensions/AppleThunderboltIP.kext
If you need to reload them (without restarting your Mac) you can run the following command in Terminal:
sudo kextload -v /System/Library/Extensions/AppleThunderboltIP.kext