Following is partly from the AutoCAD 2012 documentation with some additions and changes by me.
The plug-in auto loader mechanism allows for the easy deployment of custom applications using a package format.
The package format is a common folder structure than contains the extension .bundle in its name and has an XML file that defines the various components of the plug-in. By deploying custom applications as a BUNDLE, it makes it easier to target multiple operating systems and product releases since the parameters of your plug-in are defined in the XML file of the package. A BUNDLE can be used as a replacement to creating complex installer scripts when deploying a plug-in.
The plug-in defined by each package is loaded into AutoCAD by placing it in one of the ApplicationPlugins folders on your local drive. There are three different ApplicationPlugins folders that you can use:
- For all users:
- For all users:
- For the current user:
(Windows XP) %APPDATA%\Autodesk\ApplicationPlugins
C:\Documents and Settings\%username%\Application Data\…
(Windows Vista or Windows 7) %APPDATA%\Autodesk\ApplicationPlugins
When AutoCAD starts, both ApplicationPlugins folders are checked for plug-in applications. The packages found are automatically registered and loaded based on the metadata in the XML file of each package.
A package can be deployed using an installer, such as MSI, or manually copying the files and folder structure to the ApplicationPlugins folder. For Autodesk Exchange App downloads, deployment of the package is done using an MSI installer.
By default, plug-ins are automatically registered with AutoCAD and when a new plug-in is installed during the current session. The load behavior for plug-ins is controlled with the APPAUTOLOAD system variable. When APPAUTOLOAD is set to 0, no plug-ins are loaded unless the APPAUTOLOADER command is used.
A package can be uninstalled by removing the appropriate folder with a .bundle extension from the ApplicationPlugins folder. This can be accomplished by offering an uninstall option with the original installer or to manually delete the .bundle folder.
Note! A plug-in downloaded from the Apps tab on Autodesk Exchange can also be unistalled by going to Apps and then re-downloading the plug-in. When the download completes, you are prompted to uninstall the plug-in. Or you can uninstall it from 'Control Panel\Programs\Programs and Features' (Windows Vista/Windows 7) or Add/Remove Programs (Windows XP), just as you would uninstall any other application from your system. The panel on the Plug-ins tab will not be removed until AutoCAD is restarted.
Saved in: User-settings
Initial value: 14
0 - Do not load plug-in applications at any time
1 - Display all messages when loading plug-in applications
2 - Load plug-in applications at startup
4 - Load plug-in applications when a new drawing is opened
8 - Load plug-in applications when they appear in the plug-ins folder
How to change an Autodesk Exchange App installer from Single User to an All Users install
A static folder designed to support loading apps for the All User installation model can be found in the %PROGRAMDATA%\Autodesk\ApplicationPlugins folder.
Change the static folder installation path from the %APPDATA%\Autodesk\ApplicationPlugin (Single User) to %PROGRAMDATA%\Autodesk\ApplicationPlugins (All User). There are two ways that this can be achieved:
1) From a DOS command window:
c:\>msiexec /i MyExhangeApp.msi INSTALLDIR=C:\ProgramData\Autodesk\ApplicationPlugins AUTODESK=C:\ProgramData\Autodesk
2) You can edit the MSI directly using ORCA.exe and change the Directory Table->AUTODESK from AppDataFolder to CommonAppDataFolder