This error usually happens when the "Income of the trust estate" (Item 57) amount has been decrease or updated in a lower value after the Beneficiary distribution is already been initially completed in the Beneficiary section.
Illustration below:
- Initially the Trust Income amount is 8,996 and it was distributed

The distribution type used is "Equal", thus the total amount of 8,996 is distributed equally among the 4 beneficiaries.

Later on, it was found-out that the Income from Trust Estate amount should have been lower, that is amounting to 7,995 instead of 8,996 figure. If you click the validate button, the error "Trust estate income cannot be negative." will show because the initial total amount distributed is bigger, amounting to 8,996.

To resolve the issue, you just need to update Label W for each Beneficiary Schedule to arrived with the exact total amount in Label 51A - Income of the trust estate. Select "Manual" as Distribution Type on the main section of all the Beneficiary Schedules, then afterwards manually input the updated Trust Estate amount of for each beneficiary.
Below is the sample update of Trust Estate Income on 1 beneficiary:

Once all the beneficiary schedules was updated to arrived with 7,995 (updated Trust Estate Income total), that form should already be valid if you try to validate the form again.
