the post by samuel is correct for a type of problem but is out of date make sure you have
https://dotnet.microsoft.com/download/d ... -installerand
https://www.microsoft.com/en-us/downloa ... aspx?id=35they are the current .NET and DirectX9 packages respectively and should get through the not opening problem.
(also the DX9 link shouldn't override your current version of directx so that wont break stuff)
other then these check to make sure the fire wall isnt blocking the application by going to
windows search bar and entering "firewall"--->click on "allow an app or feature through windows defender firewall"-->"click "change settings"---> then check all the boxes.
If you cant find it as I couldn't I would recomend re installing and then allowing the .exe file to do what it wants as the file itself is kinda janky. then run it as an administrator.
after all of this I would restart your computer and after that reinstall treeit