Provided the variable may not be defined appropriately, can cause issue of missing HMI user defined variable every time the Sysmac Studio is open. This creates an issue in Global Variable table (highlighted in pink).
This issue can be sorted by implementing following method.
1.Copy/pasting all global variables of NA to Excel.
2.Deleting all global variables of NA.
3.Pasting back from Excel.
4.Downloading NA.
5.Deleting NA device.
6.Creating new NA device.
7.Uploading to new NA device.