The newly inserted object could not be assigned a key by the data source" in Sage 50
Sage 50 cannot generate an internal ID for the record you just saved, which usually points to database damage.
The message “The newly inserted object could not be assigned a key by the data source” appears when Sage 50 saves a new record, such as a transaction or a list entry, and then cannot read back the internal identifier the database assigned to it. In plain terms, the save did not complete cleanly. The software is telling you the data layer behind your company file is not behaving, not that you typed something wrong.
What the message means
Every record in a Sage 50 company file carries a hidden key that ties it to the rest of the data. When you add a record, Sage 50 writes it and expects the database to hand back that key. Here, the key never arrived or could not be read. The record may have been saved, saved partially, or not saved at all. That uncertainty is the real problem: you cannot trust the last entry, and repeating it may create a duplicate or make things worse.
Why it happens
The usual cause is damage inside the company database. A file that was closed improperly, interrupted during a backup, stored on an unreliable network share, or touched by a sync or third-party add-on can develop broken internal structures. The damage often sits quietly until a save hits the affected area. Less often, the message shows up during a data conversion or an import, when incoming records do not fit the destination structure. Which of these applies depends on the file and on what you were doing when the message appeared.
What to try first
Stop entering data and make a safe copy of the company file before anything else. Do not keep saving into it. Once you have a backup, close Sage 50 completely, reopen it, and try the same entry once. If the message repeats, restore the most recent backup that predates the trouble and compare. If the problem is recent and small, the backup may be all you need. If it comes back, the file itself is damaged and no amount of re-entry will fix it.
When the file needs professional attention
If the message appears on a fresh restore, or across several record types, the internal key structures are broken. Sage 50 has no user-facing tool that rebuilds them. Our engineers repair damaged Sage 50 and Simply Accounting databases directly, recovering the records the failed saves touched. You can send us the file for a free evaluation of your damaged Sage 50 database, and we will tell you what is recoverable before any work begins.
If this happened during a conversion
The message sometimes surfaces while moving Sage 50 data into QuickBooks or between Sage editions. In that case the source file is usually fine and the mapping is at fault. Our Sage 50 to QuickBooks conversion service handles the key structures on both sides so records land with their links intact.
Either way, do not keep working in the file after this message. Note what you were doing when it appeared, keep the backup safe, and send us the file for a free evaluation and quote.