Pastel compares the customer / supplier master files (accmasd.dat and accmasc.dat) to the transactions for each customer / supplier, for each period, in the open item file (accoi.dat).  If they do not balance, Pastel puts a balance (the OIDIFF) in the age analysis when you print it (it calculates this every time you print, it does not store it in the open item file and does not read it from there).

It puts this balance in when it finds a discrepancy, and you do not necessarily need to do anything for this to happen – you will see this reference in your age analysis.

Option A
You can convert the client to balance forward and back again (using the Change menu in Pastel) to get rid of the open item corruption.  Note that details of prior matching will then be lost.  Remember to run this option in the last period that you have processed in.

Option B
Once you have determined which period and which amount the ‘OI DIFF’ is being generated from (read the introduction) you can take the following steps:
1.    Make a Backup
2.    Create a Copy Company
3.    In the Copy Company you need to process a journal to the Customer or Supplier account in the same period for the amount difference that was generated via the Age Analysis.  This creates a record in the Open Item file.
4.    Because we only need the Open Item record you then close the Copy Company and copy the accoi.dat file from the Copy Company into the live Company and thus over-writing it with a newer file which now contains a matching Open Item record.

Option C (possibly chargeable)

Get into contact with support who will need a backup of the data to investigate the severity of the problem however this option is possibly chargeable depending on the size of the issue.