Section 12 of the Hindu Minority and Guardianship Act, 1956 does NOT affect:

The proviso to s. 12 of the Hindu Minority and Guardianship Act, 1956 states that nothing in the section "shall be deemed to affect the jurisdiction of a High Court to appoint a guardian in respect of such interest". District, civil and family courts get no such saving, so they remain barred from appointing a guardian for the undivided interest.