Zero.  Or -1 in software speak.

-1, as Susan says.  ProConnect Tax and Lacerte speak the same language.

Sorry, I wasn't clear. I have a partnership (42 partners in total) that was established in 2012. The managing partner did not keep a running balance of partnership interest or bookkeeping. All I have is the ending capital balances from the prior year's K1. I tried to add up all the ending cap balances, then break them down by percentages on the special allocation... Nothing will add up to 100%. I do have the cap table but these are the initial interests of the partners. Please advise. Thank you for your help.

Then your math is wrong. The total of the capital accounts is 100%. Each partner's capital account balance divided by the total is their %. Except for rounding they will add to 100%.