Once Simply Accounting converts your data to the Pro version" meaning
Simply Accounting upgrades your data file permanently, and the Basic edition can no longer open it after the conversion.
You are seeing this message: “Once Simply Accounting converts your data to the Pro version, you can no longer open it with the Basic version.”
In plain terms, this is a one-way door warning. Simply Accounting is telling you that the conversion it is about to run will rewrite your data in the Pro edition’s format. Once that happens, the Basic edition on your computer cannot read the file again. There is no built-in way back.
What the message actually means
The conversion is not just an unlock of extra features. It changes the data file itself. Pro and Basic use different capabilities, and the file structure is updated to match the higher edition. Basic is built to read only its own format, so after the upgrade it simply refuses to open the file.
Think of it as a format change, not a licence change. Even if you still have your Basic licence and installation media, the converted data has moved past what Basic understands.
Why this happens
Simply Accounting (sold as Sage 50 Canada, and as Peachtree in the US) offers an upgrade path from Basic to Pro when you need features the lower edition lacks. The software warns you before converting because the step cannot be undone from inside the program.
Some users hit this by accident. An upgrade prompt, a restored backup from a Pro system, or opening a file that came from a Pro edition can all trigger it. If you did not intend to upgrade, stop before confirming and read the next section.
What to do before you convert
Make a full backup of your data first, and keep it somewhere safe. The backup taken before conversion is your only way to keep working in Basic if you change your mind. Once the conversion runs, restoring that older backup is the only native route back, and you lose anything entered after it.
If more than one person or computer uses this file, confirm that everyone will be on Pro before proceeding. A converted file will not open on any workstation still running Basic.
What if you already converted and need Basic back?
If you have no pre-conversion backup, the software gives you no option. The data now lives in the Pro format. Your realistic choices are to run Pro, or to have the file professionally downgraded. Our engineers handle edition downgrades of Sage 50 data, moving a file back so the lower edition can open it again. Whether a downgrade is clean depends on which Pro-specific features the file actually uses, so we evaluate each file before quoting.
An alternative is to leave Sage editions behind entirely. If you were already considering a move, converting Simply Accounting data to QuickBooks is a well-trodden path, and it sidesteps the edition problem altogether.
A useful next step
Do not confirm the conversion until you have a verified backup in hand. If you have already converted and need the file back in Basic, send it to us for a free evaluation. We will tell you what is possible with your specific file, and give you a free quote before any work starts.