AutoIncrement fields are not supported in temporary tables

AutoIncrement relies on SQL Server to generate the next value when inserting records. Temporary tables with TableType = Temporary only exist in memory on the Business Central server — they are never created on SQL Server. When code inserts a record into such a table, the runtime cannot obtain the next auto-increment value and the insert fails.

The AutoIncrement property does not work with Dynamics 365 Business Central temporary tables.

— AutoIncrement Property on Microsoft Learn

Remove the AutoIncrement property and manage the field value in code.

Example

table 50100 "Tracking Entry"
{
    TableType = Temporary;

    fields
    {
        field(1; "Entry No."; Integer)
        {
            AutoIncrement = true; // AutoIncrement fields are not supported in temporary tables [PC0002]
        }
    }
}

Remove the property and assign the field value before inserting:

table 50100 "Tracking Entry"
{
    TableType = Temporary;

    fields
    {
        field(1; "Entry No."; Integer)
        {
        }
    }
}