Will I lose company data when downgrading Sage 50 Quantum to Pro?
No, a proper downgrade keeps your transactions and history; what changes is the feature set, the user count, and a few Quantum-only capabilities.
No, not when the downgrade is done properly. Your transactions and history carry over, and the balances built from them stay with the file. What changes is the edition wrapped around your data: the feature set, and the number of people who can work in the company at the same time.
What stays after the downgrade?
A downgrade changes editions, not books. In a properly converted file, the transactions, the history behind them, and the balances they produce are all still present. Nothing gets deleted to make the file fit Pro. Reports that draw on past periods still read the same records they always did.
What changes instead?
Two things. Pro allows fewer users than Quantum, so plan your logins before you switch. And capabilities that exist only in Quantum stop being available once the file runs under Pro. That is a feature change, not a data change. The records stay put; the tools you can point at them shrink.
Where can a downgrade go wrong?
Data loss almost always comes from the method, not the move itself. A conversion that fails partway can leave a file that will not open, or one that opens with pieces missing. Existing damage complicates things, because every record has to be read to rebuild the company in the lower edition. The protection is simple: work from a copy, and keep the original untouched until the new file checks out.
How do we verify the result?
Our engineers work from a copy, perform the edition change, and compare the result against the original before anything comes back to you. Key balances and totals are checked, so the answer to your question is demonstrated rather than assumed. The exact outcome depends on the condition of your file, which is why we begin with a free evaluation instead of a guess. You can read more about the process on our Sage 50 Quantum to Pro downgrade service page.
Your next step
Find your most recent backup and note how many people need access day to day. Send the file over for a free evaluation and ask what the downgrade involves for your data. You will have a clear answer before anything is changed, and the original stays safe throughout.