Teri is 100% spot on. A few other (hopefully) helpful notes:
- If using a catalog item for harvesting (which is the most reliable/recommended way), it must have an uninstall deployment, and you must check the box under Deployment > Global > Installation Options that says Enable Uninstallation (Remove from collection)?. If you have an uninstall deployment but you don't check that box, App Portal will still attempt to use SmartUninstall (if enabled) or will simply not attempt to uninstall (if SmartUninstall is not enabled) instead of using the uninstall deployment on the catalog item.
- If there are multiple catalog items with the same Flexera ID (ARL), App Portal will check to see if there is a previous App Portal deployment to that device and will attempt to use the uninstall deployment for the same catalog item that was used for the install deployment. If there is no previous install deployment for that device, or if the catalog item that was used to install does not have an uninstall deployment tied to it, then one of the catalog items with that Flexera ID that has an enabled uninstall deployment will be selected at "random" (it's probably not actually random, but I'm not sure what the "algorithm" is -- perhaps the one with the highest catalog/package ID, i.e. the most recently created one?).
- If using SmartUninstall, please note that the uninstall is performed by using msiexec /x <product_code> and is run in the context of the account that SCCM is configured to run under for that deployment (e.g. installer account, currently logged in user, SYSTEM, etc.). As such, if the installation was performed under the same user context, or if the installation was installed for "all users", then the uninstall should work fine. If the installation was performed under a different user context and was installed "only for the current user", the installation may fail or may leave some traces behind (e.g. Start Menu/Desktop shortcuts) because they would have been installed into a different registry hive/user profile.
Anything expressed here is my own view and not necessarily that of my employer, Flexera. If my reply answers a question you have raised, please click "ACCEPT AS SOLUTION".