Time Machine Backup failed, not enough space...
Have iMac, Yosimite OS 10.10, processor 3.1 GHz Intel Core i5, memory 12 GB 1333 MHz DDR3, internal HD - 1TB, Time machine id 1 TB external La Cie. I see that I have 260 GB left on Time Machine disk, on Time Machine window. Additional message, "Needs 266.46 GB for back up, thus "backup failed". What is my next step? Thank you very much indeed!
iMac, OS X Yosemite (10.10)