The partnership act imposes various disabilities on an unregistered partnership which are so debillating that partnership is practically indispensible nowadays. S.69 of Partnership Act, may be referred to.
IF the registration process is underway/pending - and a dispute arises - the court would not let an individual partner sue the firm for any right of his that either arises out of his contract with other partners or even those conferred by the partnership Act.
The Firm would also not be able to sue third parties for contractual rights if it is unregistered. However the Firm can do so after registration provided offcourse the claim is not time barred.
However these disabilities extend only during the lifetime of the firm, if the partners choose to dissolve it – they can file a case in court and there is no disability with respect to that.
Feel Free to ask more