Common reasons for bugs in release version not present in debug mode

Question

What are the typical reasons for bugs and abnormal program behavior that manifest themselves only in release compilation mode but which do not occur when in debug mode?

Answer 1

I just experienced that when I was calling an assembly function that didn't restored the registers' previous values.

In the "Release" configuration, VS was compiling with /O2 which optimizes the code for speed. Thus some local variables where merely mapping to CPU registers (for optimization) which were shared with the aforementioned function leading to serious memory corruption.

Anyhow see if you aren't indirectly messing with CPU registers anywhere in your code.