My single son put $1,000 into his HSA and took out $200 in 2024. Why did Turbo Tax send me a message that it was overfunded and he had to take out $1,000?

Excess HSA contributions has nothing to do with how much is in the HSA or what was spent out of it.

Instead, TurboTax has to calculate the annual HSA contribution limit based on entries by the taxpayer, and if the amount of contributions is greater than this, then there is an excess.

The fact that the excess was apparently the same as entire amount of the contribution means to me that the taxpayer did not go through the entire HSA interview and report the type of HDHP coverage he/she had.

Please go back through the HSA interview and pay closer attention to the questions, then come back here if you have specific questions.