You cannot have a negative unused RRSP contribution.
When you contribute RRSP in a given year --> you report the contribution in your income tax in the year they were made but do not deduct them and carry them forward to the next year if you wish to do so--> in the succeeding year they become unused RRSP contribution which you can choose to deduct against your income to reduce tax liability
CRA will not allow you to bring this amount bellow zero. If there is an error in the data transfer from CRA, you will have to correct it manually in the RRSP sheet.
If you have made a mistake in prior year contributions and wish to correct them, you should not change the unused contribution amount. Instead, you should file T1-Adjustment for that year when the contribution was made and attach a new schedule 7 for the RRSP changes.
If you still have issues after following this process, please contact our support line:
https://support.turbotax.intuit.com/contact/
I hope this was helpful
