Both Intuit tech support and I tried using this and failed. The situation I described is not multiple businesses. There is one business, an LLC between husband and wife, that has to file as a partnership and thus generate two K-1s for the same business. Let's call the business P2, with the partners sharing 50/50. The couple shares one workspace and thus should file one 8879 (one square footage for the office / one square footage for the home). If, in 1040 input, you enter two separate K-1s (one designated as TP, one as Spouse, so that they can match the two that the IRS receives, but both citing the same P2 and the same EIN), if you try to produce one 8879, it fails--because, in the 8879 input, you have to designate one of the P2's as the one the 8879 pulls from. In that situation, the one 8879 then picks up the business income of just one of the K-1s. The workarounds are awkward: 1) You could do two 8879s and claim 50% of the office space for each; or 2) You could add the two K-1s together and enter them as if one K-1 (thus not matching what was sent to the IRS). Note that the section you recommend is one 8879 for two businesses. This is one business. Now, since entering two K-1s for P2 gives what ProConnect thinks is two businesses, is there a way to use that allocation section to give a correct result? If so, can you be specific on what to input there?