Hello,
If you uninstall Service Release 10.3.20103.2013 for ASP.NET, you may experience an issue in uninstalling the ASP.NET product after that. The issue is that, while the product will be uninstalled from the system, its file and registry content may be left behind. This issue has been addressed for ASP.NET 10.3 service releases later than 10.3.20103.2013. Please note that you do not need to remove 10.3.20103.2013 if you want to apply later service releases. In testing so far, it is only the process of uninstalling 10.3.20103.2013 and then the RTM version that has resulted in this issue.
Workarounds for this issue would be:
1) If you want to uninstall 10.3.20103.2013 to revert back to the RTM state, reinstall the ASP.NET product instead of just uninstalling the update to keep it at a consistent installation state.
2) If you have only uninstalled the service release and then uninstalled the ASP.NET product and see the content remaining on your machine, install and uninstall the product again to have it be removed.