There may be times when you have an undefined condition tag in your project. For example, you might have a condition tag that you've applied to content and then included or excluded in some targets. But then you delete that condition tag for some reason. In that case, there are still references to that deleted condition tag in topics or targets, but the condition no longer exists in the tag set, so it's considered an undefined condition tag. If this occurs and you open the Conditional Text tab in the Target Editor (or the Properties dialog for a topic in the case of snippet conditions), you will see a reference to that undefined condition tag in the Basic view. You can then remove the reference to the undefined condition tag.
Undefined tags are highlighted with a colored background when "(show all tags)" is selected. You can remove a reference to an undefined condition tag by selecting that condition row, choosing Not Set, and saving your changes.
A listing for "(undefined tags)" also displays in the Condition Tag Sets section. Selecting this displays just the undefined tags.
If you select the condition tag set that the condition used to be in, you will not see the undefined condition tag in the list.
Note Even though you remove references to undefined condition tags, you may still have topics with references to undefined conditions. You can remove the reference to that undefined condition tag by using the Analysis Ribbon (Undefined Items > Undefined Condition Tags). You can also use the Internal Text Editor, or remove the affected content in the XML Editor and type it again.