Prevent data loss when transferring from Blender 2.79 to 2.8

[MadeWithFeet]

Hey, it’s this probably:

Can't unhide parts of model (2.8)

Hard to say without a file, but something like that happened to me from importing a 2.79 to 2.8 Visibility toggle didn’t work, models stayed hidden. You probably have your view filter set incorrectly. They are hidden by default: [2019-06-15_11-07] First row of icons controls the outliner icons.