MongoDB version mismatch
I just did a fresh build of nodebb v1.1.0 and it would not start because email@example.com had been pulled in automatically.
I was able to fix my install by manually installing firstname.lastname@example.org but obviously this isn't ideal.
P.S. The build of the older version of mongodb failed, but it didn't matter in my case since I'm using redis.
make: Entering directory `/usr/src/NodeBB-1.1.0/node_modules/mongodb/node_modules/kerberos/build'
In file included from ../lib/kerberos.cc:1:0:
../lib/kerberos.h:5:27: fatal error: gssapi/gssapi.h: No such file or directory