You have not lost any information. The depreciation information is carried forward cumulatively from year to year. All of the information is in the .tax20yy data file, not "in the software." All of your past depreciation is in the .tax2024 file. You no longer need the .tax2023 file. When you sell a property you will only need the data file for the most recent year prior to the sale. The TurboTax calculations in the future will be correct as long as you have the most recent data file.
When you use the desktop TurboTax software, you are responsible for maintaining backups of your tax return data files (the .tax20yy files). You should have backup copies on removable media, such as a flash drive or portable hard drive, or in cloud storage. There are many reasons that a file could be corrupted or lost, including software failures or failures of various parts of your computer hardware. The solution should always be to retrieve the file from your most recent backup.
