This message occurs when restoring backups, if you have selected only part of a group of tables which belong together logically and structurally.
The risk in is that the logical relation between data element be broken. In the above example, token translations entered for languages added since the date of the backup set selected will still be in the tokens table ... but there will be no way to access them since the language used to select them does not exist anymore (or rather yet, since we are restoring an earlier backup).
Worse, when you do add a new language to the languages table, it will use the ID of one of the languages that was in the table that was overwritten, and you will suddenly see translations appear out of nowhere (the same translations that were "lost" immediately after restoring the languages table.
As shown in the example on the right, this means that the left-most checkboxes should always be fully checked or fully unchecked, but never half checked as was the case in the first example, above.
Topic 171290, last updated on 17-Apr-2020