When Abiathar extensions fail to load with a FileLoadException

A semi-common issue people run into with Abiathar extensions is a failure dialog at launch indicating a FileLoadException:

Could not load file or assembly 'file:///C:\path\file.aex' or one of its dependencies. Operation is not supported.

The problem is caused by a zone identifier on the AEX file. When most web browsers download files, they add an Alternate Data Stream indicating that the file is potentially dubious because it came from the Internet. When a ZIP is extracted, the mark is added to all resulting files. .NET evidently refuses to load assemblies from files with the mark, so the above error is returned and extension loading halts.

To fix the problem, open the Properties of the downloaded AEX file and click the Unblock button. That removes the mark and lets Abiathar load the extension successfully.