Updating the Frappe.MSBuild using the Package Manager Console causes Access Denied errors when removing old version

[radleta]

Issue

The below is the output of the Package Manager Console when you update the Frappe.Mvc4 package.

Updating 'Frappe.Mvc4' from version '1.1.0.0' to '1.2.0.0' in project 'Frappe.Web.Mvc4.Razor.Example'.
Successfully removed 'Frappe.Mvc4 1.1.0.0' from Frappe.Web.Mvc4.Razor.Example.
Successfully removed 'Frappe.MSBuild 1.1.0.0' from Frappe.Web.Mvc4.Razor.Example.
Successfully installed 'Frappe.MSBuild 1.2.0.0'.
Successfully added 'Frappe.MSBuild 1.2.0.0' to Frappe.Web.Mvc4.Razor.Example.
Successfully installed 'Frappe.Mvc4 1.2.0.0'.
Successfully added 'Frappe.Mvc4 1.2.0.0' to Frappe.Web.Mvc4.Razor.Example.
Successfully uninstalled 'Frappe.Mvc4 1.1.0.0'.
Access to the path 'C:\Users\radleta\Dropbox\GitHub\Frappe\Examples\packages\Frappe.MSBuild.1.1.0.0\tools\Frappe.dll' is denied.
Access to the path 'C:\Users\radleta\Dropbox\GitHub\Frappe\Examples\packages\Frappe.MSBuild.1.1.0.0\tools\Frappe.MSBuild.dll' is denied.
Access to the path 'C:\Users\radleta\Dropbox\GitHub\Frappe\Examples\packages\Frappe.MSBuild.1.1.0.0\tools\Frappe.dll' is denied.
Access to the path 'C:\Users\radleta\Dropbox\GitHub\Frappe\Examples\packages\Frappe.MSBuild.1.1.0.0\tools\Frappe.MSBuild.dll' is denied.
Access to the path 'C:\Users\radleta\Dropbox\GitHub\Frappe\Examples\packages\Frappe.MSBuild.1.1.0.0\tools\Frappe.dll' is denied.
Access to the path 'C:\Users\radleta\Dropbox\GitHub\Frappe\Examples\packages\Frappe.MSBuild.1.1.0.0\tools\Frappe.MSBuild.dll' is denied.
The directory is not empty.

Successfully uninstalled 'Frappe.MSBuild 1.1.0.0'.

It appears MSBuild.exe still has locks on the files.

Known Workarounds

It just leaves legacy files. You can manually clean it up.

1. Close Visual Studio
2. Kill all MSBuild.exe processes
3. Delete the packages\Frappe.MSBuild* directory