I was getting the annoying "unplug the device using too much power to re-enable usb devices" notification for a while, but no USB devices were plugged in, so I just ignored the problem. Today I wanted to restart my mac, but I had a crash report after login and couldn't go further.

This is the error I got:

Anonymous UUID:       FDDD48B8-E81A-063E-D817-224A1C00BD05

Sun Jan 29 17:47:48 2017

*** Panic Report ***
panic(cpu 2 caller 0xffffff80003d255a): Kernel trap at 0xffffff7f812e6d46, type 14=page fault, registers:
CR0: 0x000000008001003b, CR2: 0xffffff810a28f274, CR3: 0x000000000374c000, CR4: 0x00000000001626e0
RAX: 0xffffff810a28f26c, RBX: 0xffffff7f812a2ca4, RCX: 0x00000000fffffdff, RDX: 0x0000000000000000
RSP: 0xffffff8109533c00, RBP: 0xffffff8109533e10, RSI: 0xffffff810a28f26c, RDI: 0xffffff80115bc600
R8:  0x0000000000000000, R9:  0xffffff810a28f26c, R10: 0x000000000083b7d0, R11: 0x0000000000000000
R12: 0x0000000000001c60, R13: 0xffffff80115bc600, R14: 0xffffff80115bc600, R15: 0x0000000000000000
RFL: 0x0000000000010286, RIP: 0xffffff7f812e6d46, CS:  0x0000000000000008, SS:  0x0000000000000000
Fault CR2: 0xffffff810a28f274, Error code: 0x0000000000000000, Fault CPU: 0x2, PL: 0

Backtrace (CPU 2), Frame : Return Address
0xffffff8109533890 : 0xffffff80002df792 
0xffffff8109533910 : 0xffffff80003d255a 
0xffffff8109533af0 : 0xffffff80003f0233 
0xffffff8109533b10 : 0xffffff7f812e6d46 
0xffffff8109533e10 : 0xffffff7f810a12f1 
0xffffff8109533e70 : 0xffffff80008b7ef8 
0xffffff8109533ee0 : 0xffffff7f810a1052 
0xffffff8109533f00 : 0xffffff8000313afa 
0xffffff8109533fb0 : 0xffffff80003ccf77 
      Kernel Extensions in backtrace:
         com.apple.iokit.IOUSBHostFamily(1.0.1)[5FF3F801-2AB5-38D2-93C2-51E00427D8FA]@0xffffff7f81099000->0xffffff7f8110afff
            dependency: com.apple.driver.AppleUSBHostMergeProperties(1.0.1)[D338A98F-2B8F-3411-BD87-BD00F620A223]@0xffffff7f81095000
         com.apple.driver.usb.AppleUSBXHCIPCI(1.0.1)[7AC984CE-8AAA-3B8D-92E3-24BE18DF3DEC]@0xffffff7f812e1000->0xffffff7f81308fff
            dependency: com.apple.iokit.IOACPIFamily(1.4)[5D7574C3-8E90-3873-BAEB-D979FC215A7D]@0xffffff7f80db3000
            dependency: com.apple.iokit.IOPCIFamily(2.9)[F398CE94-0FBD-3E8E-A7AB-55F7F05A81ED]@0xffffff7f80b2c000
            dependency: com.apple.iokit.IOUSBHostFamily(1.0.1)[5FF3F801-2AB5-38D2-93C2-51E00427D8FA]@0xffffff7f81099000
            dependency: com.apple.driver.usb.AppleUSBXHCI(1.0.1)[38F68C79-811D-3AA2-B8D4-0D444FF4DB4B]@0xffffff7f8129c000

BSD process name corresponding to current thread: kernel_task
Boot args: -x

Mac OS version:
Not yet set

Kernel version:
Darwin Kernel Version 15.3.0: Thu Dec 10 18:40:58 PST 2015; root:xnu-3248.30.4~1/RELEASE_X86_64
Kernel UUID: DECC9F02-27D7-31F0-9599-A9EF2873902C
__HIB  text base: 0xffffff8000100000
System model name: MacBookPro9,2 (Mac-6F01561E16C75D06)

System uptime in nanoseconds: 1675520687
last loaded kext at 1327218794: com.apple.driver.CoreStorageFsck    517.20.1 (addr 0xffffff7f824ab000, size 106496)
loaded kexts:
com.apple.driver.CoreStorageFsck    517.20.1
com.apple.driver.AppleFileSystemDriver  3.0.1
com.apple.AppleFSCompression.AppleFSCompressionTypeDataless 1.0.0d1
com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0
com.apple.BootCache 38
com.apple.iokit.SCSITaskUserClient  3.7.7
com.apple.iokit.IOAHCIBlockStorage  2.8.5
com.apple.driver.AppleFWOHCI    5.5.2
com.apple.driver.AirPort.Brcm4331   800.20.24
com.apple.driver.AirPort.Brcm4360   1020.17.1a1
com.apple.iokit.AppleBCM5701Ethernet    10.1.12
com.apple.driver.AppleSDXC  1.7.0
com.apple.driver.AppleAHCIPort  3.1.8
com.apple.driver.usb.AppleUSBEHCIPCI    1.0.1
com.apple.driver.AppleSmartBatteryManager   161.0.0
com.apple.driver.AppleACPIButtons   4.0
com.apple.driver.AppleRTC   2.0
com.apple.driver.AppleHPET  1.8
com.apple.driver.AppleSMBIOS    2.1
com.apple.driver.AppleACPIEC    4.0
com.apple.driver.AppleAPIC  1.7
com.apple.driver.AppleIntelCPUPowerManagementClient 218.0.0
com.apple.nke.applicationfirewall   163
com.apple.security.quarantine   3
com.apple.security.TMSafetyNet  8
com.apple.driver.AppleIntelCPUPowerManagement   218.0.0
com.apple.driver.CoreStorage    517.20.1
com.apple.iokit.IOSCSIMultimediaCommandsDevice  3.7.7
com.apple.iokit.IOBDStorageFamily   1.8
com.apple.iokit.IODVDStorageFamily  1.8
com.apple.iokit.IOCDStorageFamily   1.8
com.apple.driver.AppleThunderboltDPInAdapter    4.1.3
com.apple.driver.AppleThunderboltDPAdapterFamily    4.1.3
com.apple.driver.AppleThunderboltPCIDownAdapter 2.0.2
com.apple.driver.AppleXsanScheme    3
com.apple.driver.AppleThunderboltNHI    4.0.4
com.apple.iokit.IOThunderboltFamily 5.1.0
com.apple.iokit.IOAHCISerialATAPI   2.6.2
com.apple.iokit.IOSCSIArchitectureModelFamily   3.7.7
com.apple.iokit.IOFireWireFamily    4.5.8
com.apple.driver.AppleUSBMergeNub   900.4.1
com.apple.iokit.IO80211Family   1110.26
com.apple.driver.corecapture    1.0.4
com.apple.iokit.IOEthernetAVBController 1.0.3b3
com.apple.driver.mDNSOffloadUserClient  1.0.1b8
com.apple.iokit.IONetworkingFamily  3.2
com.apple.iokit.IOUSBFamily 900.4.1
com.apple.iokit.IOAHCIFamily    2.8.1
com.apple.driver.usb.AppleUSBEHCI   1.0.1
com.apple.driver.usb.AppleUSBXHCIPCI    1.0.1
com.apple.driver.usb.AppleUSBXHCI   1.0.1
com.apple.iokit.IOUSBHostFamily 1.0.1
com.apple.driver.AppleUSBHostMergeProperties    1.0.1
com.apple.driver.AppleEFINVRAM  2.0
com.apple.driver.AppleEFIRuntime    2.0
com.apple.iokit.IOHIDFamily 2.0.0
com.apple.iokit.IOSMBusFamily   1.1
com.apple.security.sandbox  300.0
com.apple.kext.AppleMatch   1.0.0d1
com.apple.driver.AppleKeyStore  2
com.apple.driver.AppleMobileFileIntegrity   1.0.5
com.apple.driver.AppleCredentialManager 1.0
com.apple.driver.DiskImages 417.2
com.apple.iokit.IOStorageFamily 2.1
com.apple.iokit.IOReportFamily  31
com.apple.driver.AppleFDEKeyStore   28.30
com.apple.driver.AppleACPIPlatform  4.0
com.apple.iokit.IOPCIFamily 2.9
com.apple.iokit.IOACPIFamily    1.4
com.apple.kec.pthread   1
com.apple.kec.corecrypto    1.0

I'm thinking it might be a software problem, any ideas please?
Thanky you!