Tally.ERP 9 will switch to Educational mode in case it is unable to read the TDL files. In such a scenario you have to unlink the TDL configuration pack from the respective site and create a fresh configuration pack.
To unlink the TDL Configuration pack from a site
1. Log in to the Control Centre using the Administrator’s Account ID and Password.
2. Click Tally.NET Account.
3. Select the required Account ID in My Tally.NET Account(s) screen. The Control Centre screen for the selected account ID appears.
4. Click Licensing & Configuration.
5. Select the required site in Licensing & Configuration screen.
6. Select Not Applicable in TDL Config field.
7. Press Ctrl+A to accept the changes.
Update the license to effect the changes made.