6.3 No restriction to a single invention searched 

If in response to the search opinion the applicant does not restrict the application to a single invention searched, the objection of lack of unity raised at the search stage will be reviewed and if the examining division considers that it remains valid, a first communication repeating the lack-of-unity objection raised in the search opinion will be issued.

In Rule 164(2) cases, a lack of unity objection is addressed in the communication under Rule 164(2)(b) (see also H‑II, 6.4.1).

If the applicant does not restrict the application at all, or does restrict it, but still maintains two or more inventions, the application can be refused under Art. 82 (subject to the applicant's rights under Art. 113(1) and Art. 116(1)).

If the claims still cover an unsearched invention, an objection under Rule 64 would also apply, in line with decision G 2/92 as discussed in H‑II, 6.2.

If the claims have not been simply restricted, but have instead, or additionally, been amended, such amendments can often result in the previously raised lack-of-unity objection no longer being valid, or in the arguments on which the objection was based no longer being complete. Such amendments would thus result in the objection having to be either withdrawn or at least newly argued.

Sometimes lack of unity of invention arises only during substantive examination, for example following an amendment of one or more claims so as to overcome an objection of lack of inventive step. In such situations the examining division may raise an objection, but only in very clear cases.