When you remove a topic from an instance TOC or delete a topic file, you need to check how this impacts the rest of your content:
Check all references from other topics and remove or update them.
If you want to delete the topic file, not just remove a topic from a single TOC, check all
.treefiles and remove all toc-elements referencing this topic.
Check that this topic does not contain content snippets that are reused in other topics through includes.
Place redirects from the deleted topic's URL so that users don't get the 404 error if they use the old link.
Writerside does these things automatically for you through the Delete refactoring, which is a safe way to remove a topic.
Remove topic from TOC
In the Writerside tool window, select the topic you want to remove and click or press Delete.
In the Remove TOC element dialog, select the Set redirect to option and choose the new target from the list:
At this point, you can make sure that the Update usages automatically option is selected and click Remove, but we highly recommend that you click Review usages as automatically removing all references to a topic may result in some dangling phrases.
This will open the Find tool window where you can review all usages. When you click on a usage, the source is displayed in the right pane which is a fully-functional editor where you can update references if necessary:
Click Do Refactor when you've reviewed the changes.
If you are sure you don't need this content anymore, click Delete Topic File in the confirmation dialog. If you don't, the topic will be removed from the current instance TOC, and you will be able to link it again if necessary (see Table of contents).