What version of photoshop and operating system are you using?
Do you have Pattern set as the source for the heal?
Could you post a screenshot of the settings in the tool options bar?
Adobe Photoshop Version: 14.2.1 (14.2.1 20140207.r.570 2014/02/07:23:00:00) x32
Operating System: Windows 7 64-bit
Version: 6.1 Service Pack 1
System architecture: AMD CPU Family:15, Model:4, Stepping:3 with MMX, SSE Integer, SSE FP, SSE2, SSE3
Physical processor count: 4
Processor speed: 3214 MHz
Built-in memory: 16382 MB
Free memory: 12717 MB
Memory available to Photoshop: 3255 MB
Memory used by Photoshop: 60 %
Image tile size: 0K
Image cache levels: 0
Font Preview: Medium
Does it make any difference if you use the 64 bit version of photoshop cc instead of the 32 bit version?
It seems for some reason the image cache levels and tile size reads zero, so hopefully, resettng the photoshop cc preferences will resolve the issue: