* Cleaning up Events and Attributes After Import Question

[tatewise]

If a fact is <undefined> in Tools > Fact Types... then there is no definition and is just a place-holder.
Have you read the popup message that says:

Note: this function deletes definitions of events or attributes
(or, more rarely, place-holders for undefined events or attributes).
It doe not delete or change any of the actual data you hold
about Individuals and Families in your family tree file.

If you click OK, the next popup message reinforces that saying:

One or more of the selected place-holders still has instances and consequently could not be deleted.

So if the <undefined> place-holder persists, a fact still has instances in your Project database.

Tip 1: In the Tools > Fact Types... Fact List click the Visible column header to sort the facts.
All the <undefined> place-holder facts will be clustered together at the bottom of the list.
Select them all by using Shft key method and then try to Delete them all in one go.

Tip 2: Instead of trying to build a custom Query to find each fact, use the existing ready-made Queries.
Use Query > Facts and Events > All Facts and in the Result Set click the Fact Type column header to sort alphabetically so you can scroll down to find the matching <undefined> Label/Name.
Use the All Facts Filter by Label query and enter the <undefined> Fact Label to list just those facts (partial match is allowed).
Those two methods will locate the 'rogue' facts and let you open the Property Box of each person in turn to delete the fact using the large red X Delete Fact button on the Facts tab.