Prystor remained in the Polish Army until 1925. Promoted to major, he was transferred to head the local office of Wojskowa Komenda Uzupelnien ("Army Recruiting Office") in Wilno, and together with his family, settled in the real estate at the village of Borki near Wilno (May 1925). Even though he remained a close associate of Pilsudski, he did not come to Warsaw for the 1926 May Coup, remaining in Wilno, together with Edward Smigly-Rydz. After the coup, Prystor was moved by Pilsudski to the office of the Minister of Military Affairs, and for the next three years, he followed Pilsudski, attending all meetings and military councils, including those marked as top secret.