As this error then is still happening even after “formatting the partition” and “doing another new clean install of Windows 10 LTSE Enterprise”, and has happened before with Windows 8.1 Enterprise as you advised previously, then sounds like these Windows enterprise ltse editions could be the problem and maybe not compatible in some way with eM Client or maybe not supported as yet with eM Client.
Can you install a standard (non ltse) Windows edition with your current Windows license, like Win 10 Pro instead of enterprise ?, or is your license only for the Enterprise edition. As if you could, then you should be fine as i haven’t heard of this issue with Windows 10 Pro or Win 10 Home editions.
Now if your license doesn’t work for a Windows 10 Pro install, then I would suggest you contact [email protected] and ask if Windows ltse enterprise edition is compatible with eM Client.
Note:- From what i’ve read on Windows LTSE Enterprise edition one thing is that eg: it doesn’t receive updates for years at a time. Furthermore, many features that are common place in regular Windows 10 are disabled in the LTSC version. So could be missing things or updates that are needed for eM Client.