Kernel compilation not finding .config file

Question

EDIT: Solved it, check my comment below.

I'm trying to compile a kernel with make O=$BUILD

Where build is the build path: BUILD=~/lab/build

But then I get this error:

*** Configuration file ".config" not found!
***
*** Please run some configurator (e.g. "make oldconfig" or
*** "make menuconfig" or "make xconfig").
***
make[3]: *** [silentoldconfig] Error 1
make[2]: *** [silentoldconfig] Error 2
make[1]: *** No rule to make target `include/config/auto.conf', needed by`include/config/kernel.release'.  Stop.

Before I compiled I used the old config file for the new kernel by copying it to my kernel folder:

cp -vi /boot/config-3.13.0-45-generic .config

and then i ran:

make oldconfig 

and entered all defaults.

How can I fix the error?

Answer 1

I got it to compile now by doing make O=$BUILD oldconfig and also by doing a make mrproper in my kernel directory, and then running make O=$BUILD again.