I've had this post rattling around in my head for a few months now, but I've never had enough hard data to really flesh it out as well as I'd liked.
I still don't, but I need to get this down on paper.
Apps deployed via Group Policy expire from the local cache. This can be a problem if the app is removed from the servers, or if you make changes to an existing app that would make its MSI not match the installation (Product/Package code changes, etc).
I don't have the details as to why - whether it's the oldest that gets purged, or least commonly used, or largest; whenever the problem has been seen here, it gets fixed first and the why gets worried about later. I'd hoped that the next batch would last long enough for me to dig out the details but no such luck.
Want to reproduce the problem? Simple:
1. Publish an app via Group Policy. Let thousands of people install it.
2. Let it sit for a while (like I said: I don't have the details as to what causes it to expire)
3. Change the product code in the MSI on the server.
4. Try to uninstall the package on the client. MSI not found, tries to recache from the network, not found there either.
Ran this past a coworker who is an MSI guru; he ran it past his folks and nobody had heard of MSIs not staying in the local cache. It is entirely possible that it's something specific to our implementation (a policy setting?). It seems to manifest itself as the same old "Installation Source cannot be found" message when users attempt to repair, uninstall, or upgrade an app.
Have you seen this? Do you know anything more about it?