Time Machine to recover OS X system error

Apple MACBOOK PRO 13-inch 15, the system OSX: 10.11.6, WD Western Digital My Cloud 3.5 inch USB3.0 4T.
Enter Time Machine Enter the user name and password to the open file that appears: An unexpected error occurred while trying to open the backup (Error 3).
Who knows what the problem is? ?? ?? More than 180 G’s backup Yeah, but also can not be saved


Please try resetting the unit using the 4 seconds method using the reset button on the back of the unit and try that again.

I have copied to the mobile hard drive, in the machine time into the recovery is still the problem. Should not be a problem. 180GB backup ah can be saved?