blender import only two types of file format: .dae; .abc, all other formats are enabled and save in edit, preference, addon, such as obj do not appear in the import / export list, no errors appear
(example: 2.79b release)
(example: 2.80, edbf15d3c044, blender2.8, 2018-11-28, as found on the splash screen)
Short description of error
Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).