If I'm trying to convert sage 50 , 2018.2 to quick books desktop that will be sent to final destination quick books online but the conversion tool just won't work !
I'm excited to hear that you'd like to join the QuickBooks family and we'd love to have you with us! I want to make sure you have the options for converting your Sage 50 to your QuickBooks product of choice and am happy to go over the options with you.
At this time, there isn't a way to convert Sage 50 to QuickBooks Desktop, but luckily, there is a way to convert it to QuickBooks Online. Since you say this is your final destination, I encourage you to skip the step of converting to QuickBooks Desktop and go straight from Sage 50 to QuickBooks Online.
The process has been made even simpler and puts you in the driver's seat as you use a service called DataSwitcher to convert your Sage 50 data to a QuickBooks Online account. I've got a few links here that can help you with this process.