Operating system: macOS 10.14.1
Graphics card: AMD Radeon R9 M295X
version: 2.80 (sub 35), branch: blender2.8, commit date: 2018-12-03 23:39, hash: 1b6a394d862, type: Release
build date: 2018-12-04, 01:09:28
When exporting a simple mesh as FBX using the 'Tangent Space' option an error occurs and no FBX file is created.
Based on the default startup or an attached .blend file (as simple as possible).