transfer of property through unregistered deed

No, such type of transfer are not valid in eye of law.For valid transfer document ( sale deed ) must be registered before sub registrar. Claiment neither can get legally possession nor can file suit for specific performance as being time barred.

It is no (NO) sale / purchase transaction in the eyes of law.

Sale deed must (mandatory) be registered with concerned Sub-Registrar.

Certain states are contemplating to get registration of such properties as a one-time measure to get revenue and they are taking possession as per revenue/panchayat records as authentic.  If there is no delivery of possession, the case is weak for the purchaser as purchase and possession are integral unless there is a contrary clause in such sale deed.

No. Not valid.

Why claimant did not took possession ,what is Ur contention ,who is objecting ,issue legal notice thru advocate ,if they come to compromise ,compromise if not go to court engaging eminent advocate filling his pocket with  fee ,see next .

What is the issue if the claimant has not taken possession?  Has he paid the consideration, at least in part?