Hello Everyone, I’m having a problem backing up my Sambapos V5 database after connecting to SQL server 2016, below is the error i receive 
Your help will be much appreciated.
Have you ever backed up before on this machine?
If not you should search “backup and permissions” as you just need to give permission to the NT Service to write to the Directory.
User folders are locked down by default. I recommend using an external drive or create a specific folder for it outside of users dir.
You could change permissions but if your not sure what your doing just choosing a different location might be better.
How to change the backup location in the sambapos software
You click settings from the database backup module and change it.
Thank you very much, your solution have solved my problem.