Hi
Rene,
We are not providing toolbox support ASPNET CORE. We provide only
extension support.
The installation issue might occur due to
any of the below reasons,
- Any Windows OS update
pending in your machine. Please check whether any Windows update is pending
in your machine, if pending please update, restart, and
try the installation again.
- .NET Frameworks not
properly installed in the machine.
- If Visual studio
is not installed properly.
Please install the setup by deselecting the extension option
during the installation process.

Follow the below documentation link
to install the extension manually into your visual studio:
https://ej2.syncfusion.com/aspnetcore/documentation/visual-studio-integration/download-and-installation
In the meantime, please share the following details it would help
us to investigate the problem further.
- Please
share information about the gatherlog tool so that we can investigate the
reported issue further.
https://support.syncfusion.com/kb/article/2865/gather-log-file
- Installed Visual
Studio versions.
- Windows OS version(Run->
Type ‘winver’
If we misunderstood your query, could you please share the detailed
information regarding the issue you are having while using the setup?
Please let us know if you need
any further assistance.
Regards,
Prashanth S