How to Stop Quicken From Overriding Manually Entered Split Categories (Q Mac)

Qunbee

Quicken just ignored a manually entered transaction which matched in dollar amount but had split categories. This has not happened before. How can I get Quicken to recognize the split category transaction and not add an additional transaction in the same amount to the ledger? (I have searched, read, searched and read, etc. etc. but if I do find an entry on the forum which might answer this problem, clicking on it leads to a "503 error".)