I had already tried to install Paint.Net v5.0 from the offline installer. I had exactly the same problem. Error message to have a more recent version of Windows.
I unzip the zip file in a folder before launching the installation. After the installation, I launch Paint.Net from the shortcut of the start menu. I also tried directly from the folder "C:Program Files\paint.net" by running paintdotnet.exe.
I had also disabled my Antivirus. Then i uninstalled Paint.Net and installed it again. Still the same error.
Today I got the version 5.0.1. Still the same error message after installing the offline installer.
I test with the portable version (in download folder) and it works !? 😉 .
I copied the folder of the portable version to the installation folder (robocopy /MIR) . Still the same error.
So I looked at the properties of paintdotnet.exe and i realized that I have a compatibility mode on Windows 7. By deactivating it, the software launches correctly.
Here is the cause of the problem. The information of the compatibility mode is stored in the registry of the user (possible also in HKLM) : HKEY_USERS\SID_USER\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers.
This information persists in the registry even after uninstalling the software and/or deleting the file/folder.
