The tally.ini file is where all your startup configurations are stored. If it is corrupted, Tally cannot read it.
The loss of application settings in TallyPrime is generally attributed to one of the following technical root causes:
During upgrades, the tally.ini file may still point to a legacy Tally.ERP 9 directory instead of the current TallyPrime installation folder.
Pro tip: Prevent future headaches — schedule automatic backups and keep a copy of your Tally data folder in cloud storage.