'APP Blocked for my protection ! - AGAIN !

Am sorry to post on this subject (like many others before me) but I am at my wits end.
I have been plagued by this for a month or so now.
Out of the blue on my W10 Pro (19043.1466) Desktop PC I cannot open one particular App (.exe) without the dreaded red notice.
I have researched and researched , tried 101 sure fire fixes all without success.
Tried with all virus software/firewalls etc etc switched off.
I have contacted the 'client' at the other end who have not had anything similar from anyone else - but as the App runs on my laptop (also W10) it just has to be an issue with my UAC/Desktop.
I can however open the App if I temporarily disable UAC (via RegEdit, LUA) but UAC on/off isnt practicable as I use the App frequently.
Whilst I am reasonably competent on the PC so far I have avoided what looks like really 'heavy duty" solutions
Can anyone think of what I should do next ?
Thanks,
Wombat

Thanks Salchina for 'high speed' reply.
The two .exe files that generate the 'red message' are :
navigraph fms data manager.exe
SimBrief Downloader Setup 1.6.3.exe
Both access and enable the download of certain Flight Simulator navigational data.
Downloads come from a Company called 'Navigraph' (Navigraph) who maintain up to date databases of navigational information for real world airlines (and flight simulation).
Sorry about out of date PC info - it looks like I havnt be on the forum for a long time !
I will update later.
Let me know if you need more info.
Thanks,
Wombat

Hello Again,
Yes both set as 'Unblocked'. In fact to make sure I have temporarily turned off Smartscreen. Same result though.
I have indeed contacted Simbrief's support. They had a good look but as I had copied the .exe files to my Laptop - and they worked from there - I didnt have much of an arguement with them.
They advised on temporarily disabling UAC (via RegEdit, LUA) on the Desktop which works - but that isnt all that good as I use the .exe files fairly regularly.
I logged in to Simbrief but had no luck with version numbers.
However logic suggests (to me at least !) that given there are no problems with the same .exe files when run from the Laptop, the problem has to be something that is confined to how W10 is running on my Desktop.
Maybe I should hang in there and keep trying ?
Wombat

Me again, the plot thickens !
In your last email you touched upon something that got me thinking.
If I had merely copied to my Laptop a Simbrief/Navigraph .exe file (one that doesnt work on the Desktop) then I agree it shouldnt work on the Laptop - but it does !
So following a search yesterday I found the program had indeed been installed on the Laptop in AppData/Local/Programs ! Certainly not by me - presumably Navigraph when I first double clicked the .exe file.
As AppData is hidden by default I had no knowledge of its existence but it explains why it works.
So a question now comes to mind.
For reasons unknown the same .exe file wont/cant be run on the Desktop (the program is NOT installed in AppData on the Desktop as it is on the Laptop).
What then if I copied the the program from the Laptop to AppData in the Desktop ? I Immediately think of Registry issues where I am definitely not qualified to go !!
I have to be away for a week so absolutely no rush for a response.
Incidentally I do have a Macrium back up of the whole Desktop but I am a bit reluctant to do a full restore - with my luck I could end up with nothing at all !
Wombat

You are right.
Of course the problem is I want to properly install the program as somewhere down the track I have stuffed something up, but every time I try to properly install it I am blocked by UAC.
Ah well, am away for a short while - will give it lots more thought.
Ayway, thanks for help so far.
Wombat