LibreOffice Calc prompting to update "links to other files". Why?

Solution 1:

You have the choice to embed or link to an object when you insert content into your document from another source. Paste Special also gives you a choice to link objects from the clipboard.

Each method has it's own benefits. With embedding, all the content is contained within a single file. This simplifies distributing documents or moving them around, as all the content moves together. On the other hand, linking reduces redundancy, by having a single source for an object. A link's path can be relative or absolute.

Since you are receiving a message about linked objects in your file, the Edit > Links command will highlight them for you. You can then remove the links and the objects will instead be embedded.

Example:

Update:

I am having issues with Break Link in LibreOffice 3.4.5. It should be removing the links and embedding the latest contents, but the link persists after saving and closing.

Solution 2:

Sometimes this can happen because of pasting a formula from another sheet that references something not in the current sheet (giving a #REF! error), then deleting it again.

It can be easily fixed by going into Insert > Names > Manage and deleting the problem named reference. (Shortcut: Ctrl+F3).

Credit to this answer, but I note someone had asked here as well.