Hi  Irene Li ,

Thanks for reaching out. Which edition of Sage 50 Canada did you have previously? Sounds as though it may have been the Premium edition and now the file is being opened with Sage 50 Canada version 2024 Pro edition which is a step down. The database structure is different between these editions and cannot be directly downgraded. 

While it's possible to recreate the data file, it's typically best done at year-end. If you're considering this at year-end, remember that you cannot export/import transaction history.

Your primary option would be to export reports like the trial balance (for account opening balances) and lists of client, vendor, project, stock, chart of accounts, and price list info. This requires familiarity with Excel. For guidance, please check this step-by-step link. Alternatively, a Sage Accountant's Network member can assist with exporting your data.

Warm Regards, 
Erzsi