There are several possible reasons for this errors message.
1. Run Disk Utility and choose Repair (the whole disk and the Macintosh HD). Try BCA.
2. Boot in Safe Mode - OS X: What is Safe Boot, Safe Mode? - Apple Support and then boot normally and try BCA.
3. Run SMC Reset and NVRAM Reset and try BCA. You may have to do this twice.
a. Resetting the System Management Controller (SMC) on your Mac - Apple Support
b. How to Reset NVRAM on your Mac - Apple Support
4. If you are here, you do not have sufficient contiguous disk space on your disk to move partitions/relocate files due to fragmentation. Use the following steps.
a. Back up your OSX installation using Mac Basics: Time Machine backs up your Mac - Apple Support
b. Erase your internal drive using Internet Recovery - OS X: About OS X Recovery - Apple Support. If your Mac does not support Internet Recovery, locate the Grey disks that came with your Mac for an erase/install.
c. OS X Yosemite: Recover your entire system from the back up made in Step 4a.
5. If none of these work, you may need an appointment at the local Apple Genius Bar, where diagnostics are free.