What should be the implementation strategy?

what is the best implementation strategy? Customization + go live or finish customization then go live at the start of a accounting period? i am working on a customization + live navision implementation project and 'cause the project is online for a few modules. the coy is using payroll for more than 1 year and now they want all the backlog to go into the system for rest of the modules and verified. i started doing so getting all the data from january till date into navision some thru dataports and some by manual data entry. But when i started running the trial balance report out of navision, i was lost…and the data seems to be a mess…with the customer and vendor balances being wrong, export figures not tallying with their account books…and it took me arnd 15 days to check and correct data. what do u guys suggest? whould i go on for monthly data checks or jus post all the transactions till date and then balance everything to date? help me am in a fuss…

This is a huge topic! It is not a simple operation to migrate data into a new ERP system and take heart that many people work hard on this. I suggest that consider the implementation from two requirements: data migration and user acceptance testing. For data migration Make sure the mapping is accurate; Make sure that source data is accurate; Identify (and document with your user) the reconciliation points; Move data into a test or QA environment before commiting to a live / production environment. Measure three time and cut once. Secondly, develop and test in a dedicated environment and make your user test the changes and validate that the changes conform to requirements before moving to a live environment. Object changes could be divided into critical and trivial groups and implemented accordingly. Move changes to the live database slowly and carefully. And make sure you have at least one security copy of the data and objects before making any changes.