This is the report that was captured after the most recent crash (it means nothing to me!):
Anonymous UUID: 822F27BF-3E21-E25D-7633-8F8CFFE82DDA
Wed Jan 28 09:10:54 2015
*** Panic Report ***
Machine-check capabilities: 0x0000000000000c07
family: 6 model: 58 stepping: 9 microcode: 21
signature: 0x306a9
Intel(R) Core(TM) i7-3667U CPU @ 2.00GHz
7 error-reporting banks
Processor 0: IA32_MCG_STATUS: 0x0000000000000005
IA32_MC3_STATUS(0x40d): 0xbe00000000800400
IA32_MC3_ADDR(0x40e): 0x00003f7fa326f37c
IA32_MC3_MISC(0x40f): 0x000000000003ffff
Processor 1: IA32_MCG_STATUS: 0x0000000000000004
IA32_MC3_STATUS(0x40d): 0xbe00000000800400
IA32_MC3_ADDR(0x40e): 0x00003f7fa326f37c
IA32_MC3_MISC(0x40f): 0x000000000003ffff
Processor 2: IA32_MCG_STATUS: 0x0000000000000004
IA32_MC3_STATUS(0x40d): 0xbe00000000800400
IA32_MC3_ADDR(0x40e): 0x00003f7fa383cd6d
IA32_MC3_MISC(0x40f): 0x000000000003ffff
Processor 3: IA32_MCG_STATUS: 0x0000000000000005
IA32_MC3_STATUS(0x40d): 0xbe00000000800400
IA32_MC3_ADDR(0x40e): 0x00003f7fa383cd6d
IA32_MC3_MISC(0x40f): 0x000000000003ffff
panic(cpu 1 caller 0xffffff802241f12a): "Machine Check at 0xffffff7fa326f37c, registers:\n" "CR0: 0x000000008001003b, CR2: 0x000000010a35d000, CR3: 0x0000000025272000, CR4: 0x00000000001626e0\n" "RAX: 0xffffff812b25e010, RBX: 0x0000000000000000, RCX: 0x38d4d359698d0037, RDX: 0xffffff81239fc088\n" "RSP: 0xffffff814b943b40, RBP: 0xffffff814b943b80, RSI: 0xffffff81239fc068, RDI: 0x0000000000000000\n" "R8: 0x00000000009891e0, R9: 0xffffff81239fc068, R10: 0x00001821f6529797, R11: 0x00001821f5ba05b7\n" "R12: 0xffffff80f3939000, R13: 0x00000000ffffffff, R14: 0x0000000000000000, R15: 0xffffff8022b0ae74\n" "RFL: 0x0000000000010202, RIP: 0xffffff7fa326f37c, CS: 0x0000000000000008, SS: 0x0000000000000000\n" "Error code: 0x0000000000000000\n"@/SourceCache/xnu/xnu-2782.1.97/osfmk/i386/trap_native.c:1 68
Backtrace (CPU 1), Frame : Return Address
0xffffff8123965e90 : 0xffffff802233a811
0xffffff8123965f10 : 0xffffff802241f12a
0xffffff8123966070 : 0xffffff802243acef
0xffffff814b943b80 : 0xffffff7fa3271a68
0xffffff814b943bb0 : 0xffffff7fa326e261
0xffffff814b943c00 : 0xffffff7fa30ad4b0
0xffffff814b943ce0 : 0xffffff7fa326f830
0xffffff814b943da0 : 0xffffff7fa32719dd
0xffffff814b943e00 : 0xffffff7fa3274973
0xffffff814b943e50 : 0xffffff7fa3274aa6
0xffffff814b943ea0 : 0xffffff80228db3cd
0xffffff814b943f00 : 0xffffff802236be13
0xffffff814b943fb0 : 0xffffff80224192c7
Kernel Extensions in backtrace:
com.apple.iokit.IOUSBFamily(705.4.14)[E15E9DC8-410F-3612-8371-E5FECD939E0D]@0xf fffff7fa30ab000->0xffffff7fa310ffff
dependency: com.apple.iokit.IOPCIFamily(2.9)[766FC23F-452C-3B74-951C-598BB17BCF06]@0xffffff 7fa2b24000
com.apple.driver.AppleUSBEHCI(705.4.14)[8DF38F62-9C2F-3A62-B6AD
Model: MacBookAir5,2, BootROM MBA51.00EF.B02, 2 processors, Intel Core i7, 2 GHz, 8 GB, SMC 2.5f7
Graphics: Intel HD Graphics 4000, Intel HD Graphics 4000, Built-In
Memory Module: BANK 0/DIMM0, 4 GB, DDR3, 1600 MHz, 0x02FE, -
Memory Module: BANK 1/DIMM0, 4 GB, DDR3, 1600 MHz, 0x02FE, -
AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0xE9), Broadcom BCM43xx 1.0 (7.15.124.12.10)
Bluetooth: Version 4.3.1f2 15015, 3 services, 27 devices, 1 incoming serial ports
Network Service: Wi-Fi, AirPort, en0
Network Service: Display Ethernet, Ethernet, en2
PCI Card: Apple 57761-B0, Ethernet Controller, Thunderbolt@191,0,0
PCI Card: pci11c1,5901, IEEE 1394 Open HCI, Thunderbolt@190,0,0
PCI Card: pci12d8,400e, USB Open Host Controller, Thunderbolt@196,0,0
PCI Card: pci12d8,400e, USB Open Host Controller, Thunderbolt@196,0,1
PCI Card: pci12d8,400f, USB Enhanced Host Controller, Thunderbolt@196,0,2
Serial ATA Device: APPLE SSD SM512E, 500.28 GB
USB Device: Hub
USB Device: FaceTime HD Camera (Built-in)
USB Device: Hub
USB Device: Hub
USB Device: Apple Internal Keyboard / Trackpad
USB Device: BRCM20702 Hub
USB Device: Bluetooth USB Host Controller
USB Device: Hub
USB Device: HP LaserJet 400 color M451dn
USB Device: Apple Thunderbolt Display
USB Device: Display Audio
USB Device: FaceTime HD Camera (Display)
Thunderbolt Bus: MacBook Air, Apple Inc., 23.4
Thunderbolt Device: Thunderbolt Display, Apple Inc., 1, 26.2