I've been getting reports from multiple sources indicating that there's a problem with the Pack Installer.  The symptom seems to be an exception thrown at startup.  If you see this message:

 see the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.Data.ConstraintException: Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.
at System.Data.DataSet.FailedEnableConstraints()
at System.Data.DataSet.EnableConstraints()
at System.Data.DataSet.set_EnforceConstraints(Boolean value)
at System.Data.XmlDataLoader.LoadData(XmlReader reader)
at System.Data.DataSet.ReadXml(XmlReader reader, Boolean denyResolving)
at System.Data.DataSet.ReadXml(String fileName)
at Microsoft.VSPowerToys.PackInstaller.PackInstallerForm.LoadPackFeed()
at Microsoft.VSPowerToys.PackInstaller.PackInstallerForm.mgr_TaskCompleted(Object sender, TaskCompletedEventArgs e)

then you're getting the error.  I believe the problem is that when I released the Beta of Pack Installer I broke the already released Alpha.  The core technical issue is that I updated the schema for the Beta and changed the format of the feed file used to get the list of tools.  Unfortunately I used the same forwarding link to point to the new file as pointed to the old one.  Since the link is now updated anyone using the Alpha is broken.  This was careless on my part and unfortunately all I can do at this point is apologize to anyone who tried to use the tool and had it break. 

 The solution to the problem should be to run the Beta version instead of the Alpha.  If this problem persists, please let me know and I will look into it even further, but I am pretty sure this is the cause of the problem, at least it repro'ed on my machine this way, and I hope there isn't another bug in the software.

 Thanks for your patience,

-Jeremy