# Installation Troubleshooting

## Trouble installing Numbuf

### Arrow fails to build
If the installation of Numbuf fails, chances are there was a problem building
Arrow. Some candidate possibilities.

#### You have a different version of Flatbuffers installed

Arrow pulls and builds its own copy of Flatbuffers, but if you already have
Flatbuffers installed, Arrow may find the wrong version. If a directory like
`/usr/local/include/flatbuffers` shows up in the output when installing Numbuf,
this may be the problem. To solve it, get rid of the old version of flatbuffers.

#### There is some problem with Boost

If a message like `Unable to find the requested Boost libraries` appears when
installing Numbuf, there may be a problem with Boost. This can happen if you
installed Boost using MacPorts. This is sometimes solved by using Brew instead.

## Trouble installing or running Ray

### One of the Ray libraries is compiled against the wrong version of Python

If there is a segfault or a sigabort immediately upon importing Ray, one of the
components may have been compiled against the wrong Python libraries. CMake
should normally find the right version of Python, but this process is not
completely reliable. In this case, check the CMake output from installation and
make sure that the version of the Python libraries that were found match the
version of Python that you're using.