I have also had this issue. I don’t recall what the solution was exactly but it would happen mostly if users did not have their Office updates installed.
The splash screen would show briefly then Excel would close. Once they updated their Office (usually because they buy older Office 2010-2016 on eBay and still need updates) then all would be fine (this happens also with DoneEx product).
I also have issues with Office 365 forcing the Excel ‘app’ as the default Excel program (rendering all vba functions useless and giving clients the VBA error instead).
This has been a nightmare for me. The clients see their Excel as a locally installed (desktop) Excel version (2016-2019) that they paid for. In reality once I logmein to their PC I find that even though they do have the downloaded (Desktop) version of Excel installed, that Excel 365 (click to run) is actually opening it.
(To test: just click any normal .xls file and see what opens it, as this is the default Excel that XLS Padlock uses).
Also, once 365 is installed, even if you uninstall it, it still forces the (free) app as the default Excel! I have to make the clients use the Office 365 removal tool and completely remove 365 and then have them buy Office 2016 Pro or re-install (or repair) their older Excel just to fix it!
Since you cannot open the compiled file with Excel itself (like you can with any normal .xls file), it would be nice if XLS Padlock had a way to select which version of Excel to open it with (from a list of installed Excel versions on the PC)! Otherwise, whatever MS decides to force as the default Excel (now and in the future) can render your VBA useless, and it gives us developers a black eye as our users think we have bad vba code! (until we prove otherwise by removing all traces of Office 365, than all works fine!).