If one forgets to say ya’aleh v’yavo at Minchah Friday Rosh Chodesh, and Shabbos is NOT Rosh Chodesh, it is a major shayloh if one can daven ma’ariv twice.Such a case (where you will not be saying yaaleh veyavo at the make-up tefillah either) is a general shayloh even if it occurs during weekdays, and the aytzah given is to daven the second Tefilla as a nedava, which cannot be done on Shabbos.
MB says one maariv only.
A.HaShulchan is noteh –2.
Rav Malinowitz says: DON’T FORGET YA”ALEH V”YAVO AT MINCHA!!
Sefarim write how the Shechinah is ‘pained’ when people speak d’varim b’tailim in Shul. Ultimately, it ‘drives out’ the Shechinah….Cerainly something to think about in these days of churban HaBayis.