+## Troubleshooting
+
+1. Example program crashes with SIGILL (Illegal instruction).
+
+ Your CPU probably doesn't support AVX instructions which is used by dlib.
+ You can confirm this by running
+
+ grep avx /proc/cpuinfo
+
+ If this is the case, try to find out if your CPU supports SSE4 or SSE2,
+ then edit "build.sh" and "example/demo.patch" to change
+ `USE_AVX_INSTRUCTIONS=1` to `USE_SSE4_INSTRUCTIONS=1` or
+ `USE_SSE2_INSTRUCTIONS=1`.
+