I have a user on 10.4 Desktop whose Find tool (Features tab) does not populate with the layers in the TOC. The list is simply blank ,and there are many layers in the TOC. He gets around this by typing in the first letter of the layer name, which he has memorized out of habit (p for parcels layer, for instance), and then that layer name shows up as an option in the tool and he can select it by clicking it or hitting enter. But the full list never populates.
I suspect he may not have enough RAM or processing power, but I do not know, and a search for this issue uncovered nothing. He's got 4GB of RAM right now.
I previously disabled his Find tool from reaching out to ArcGIS Online for the World GeoCode Service and MGRS locators in the Locations tab. I did this because that reaching out to ArcGIS online the tool would take a minute or more to load and nearly crash his computer. I made the change by making the appropriate code changes in the DefaultLocators.xml and I cut the connection ArcGIS Online in the system tray. I don't think these changes caused the above issues at all, but I should mention it.
Any thoughts are appreciated.