If you look at the help for how to get last years AGI in order to e-File, they don't give you the one thing that will definitely get it for you. Their best answer is to file it by mail!!! I ran in to this situation this year (2025 for 2024's tax returns)! My PC burped and my entire Tax directory got wiped out! I couldn't find anything in Trash! And I normally have Seagate backup system running. However, this is a pretty new PC and I didn't get one for it yet!
So, I went to the IRS website and , lo and behold, they have a list of the last few years of your tax information, not in tax form format, but in field name/field value format!!! A quick search on Adjusted Gross Income and, voila, I got what I needed! Just thought, if anyone ever needs info from a back tax form, now you know where to get it!