Upgraded a 9.3 File Geodatabase to 10.x.
ArcGIS for Desktop 10.5.1 has no issues... ArcGIS Pro 2.0.1 will not display any contents.
I have reviewed ArcGIS Pro 1.2 Doesn't "see" .mdb or .gdb and tried
"For the GDB problem - create a folder connection to the folder ABOVE the GDB and make sure the GDB is not inside a folder with the same name (or anything else .gdb) - I've seen issues with that sort of nested folder before."
However that seems to have no effect...
I followed the instructions to fix a Personal GeoDB and that worked for my 9.x File GeoDb...
Modify your data sources to a supported type with 64-bit ArcGIS. Using the Create File GDB tool, you can create a file GDB and then import your layers into it using the Feature Class to Geodatabase (multiple) tool.
So, File GeoDB's upgraded from 9.x are not supported in ArcGIS Pro?
Are you referring to this tool Upgrade Geodatabase
Yes. Also tred the GeoDB properties window / upgrade function.