The errors of complete omission do not affect the Trial Balance. But the errors of partial omission would certainly cause disagreement of the Trial Balance because they would lead to either short debit or short credit.

Errors like double posting, wrong totaling, wrong carry forward, wrong balancing etc. are also regarded as errors of commission. Such errors usually cause disagreement in the Trial Balance. But, the error$ committed while recording the transaction in subsidiary books or posting it to a wrong amount (but with correct amount and on the correct side) do not affect the Trail Balance.

While posting an entry of Rs. 200 to the debit of Ram’s Account we wrongly wrote Rs. 400. Then, while posting an entry of Rs. 500 to the debit of some other account we wrote Rs. 300. The first error led to a higher debit of Rs. 200 whereas the second error resulted in a lower debit of Rs. 200. Thus, the effect of the first error is nullified by the effect of the second error. Take another example. The Purchases Journal is overcast in excess by Rs.1,000 which means the Purchases Account will be debited in excess by Rs.1000. The Sales Journal also, by mistake, is overcast, by Rs.1,000 whish means the Sales Account will be credited in excess by Rs.1,000. These two mistakes, together, result in an excess debit of Rs. 1,000 as well & an excess credit of Rs. 1,000. Thus, they cancel out of the effect of each other. Such errors do not affect the Trial Balance.