message keeps coming up saying 'record already exists' when trying to post a transaction
This error means that the document number that Sage is trying to assign to the transaction has already been used for another transaction. If you are using the auto-numbering function and letting Sage assign document numbers, the numbering can get out of sequence if a user has manually input a document number, overwriting the ***NEW*** number. Sage does not increment the next document numbers for any that it has not automatically assigned, that have been manually entered, even if they are they next number in line. For example if the next document number is 25, and someone manually enters 25 into the document number field and posts that transaction, Sage still tries to assign 25 to the next document posted - and you will get this error.
You must adjust the next document number to resolve the error and get the auto-numbering back in sequence. For whichever module you are having the trouble, go to Setup / Options - and click on the Documents or Document Numbering, or Numbering Tab. Increase the number of the transaction ahead of the last document number posted and save. You will need to be the only one in Sage to change this screen.
See also: Record Already Exists