Windows Username Not Found In Security File - Spreadsheet Server

Here is the link to the Insight article on this: https://help.insightsoftware.com/support/s/article/Windows-Username-was-not-found-in-Security-file?language=en_US

Can be caused by the user not being able to connect to HBFILE/HBREPORTS - check the VPN connection, and have the user restart before following steps below:

Log into HBREPORTS
Open Application Configurator, enter password gsi
Check if the user in question has a license, and if the username is spelled correctly
If this everything looks correct there, remote into the user's PC, and open the spreadsheet server settings in the top ribbon
Ensure that the highlighted field below matches this filepath EXACTLY - \\hbfile.hbdomain.local\dept\Admin\Spreadsheet Server

Hit Ok, and restart Excel
The issue should be resolved - if not, reach out to the data team.