Upgraded desktop to 10.5 last week, but found today that 2 locators within a geodatabase do not show in 10.5, but when viewed on a 10.3 and 10.4 they show. I did not have the same issue when upgrading from 10.2 to 10.3 and 10.4.
Solution to this issue other than rebuilding locator?
As mentioned in the below web-link:
" Locators should be stored in a file folder so you take advantage of new features that are not supported for locators stored in geodatabases, such as performance improvements, multithreading capabilities, and suggestions support. ArcGIS 10.4 is the last release to support storing locators in geodatabases. "
Here is the web-link for reference: