Thank you for your reports - we highly appreciate the feedback.
I can confirm that we identified an issue with Microsoft Security Essentials
and Microsoft Windows Defender
which are giving false positives about the Telerik.BlackDragon.Common.dll
assembly. These antiviruses are locking the assembly and thus preventing the load of AppBuilder
We are already working on a fix but in the meantime I would suggest adding the assembly to the whitelist of the antivirus application. This, of course, is just a temporary workaround and we will provide a proper solution as soon as possible.
Please accept our apology for the inconvenience caused.