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derekf's blog On C#, repackaging applications, and deploying via group policy...

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?

Posted on Monday, December 10, 2007 1:22 PM | Back to top

Comments on this post: Apps Expire from local MSI cache

# re: Apps Expire from local MSI cache
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When you change the product code in the MSI on the server does this update the product code on the client? If it does then that is why you cannot uninstall, because that product code is not there to uninstall from. I have heard that SMS removes the oldest msi's from cache when space is required for a new install. This happenes when a certain sms cache size maximum is reached. I think this is a % of your hard drive size.

Left by Padraic Waters on Jun 04, 2008 4:50 AM

# re: Apps Expire from local MSI cache
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Changes to the MSIs on the source do not propogate to the clients. In fact, even with those methods to forcibly update (redeploy or repair with the recache option) don't allow you to change the product code.

As for SMS removing the oldest MSI from the cache, I'd believe it; we do have SMS in our environment.
Left by derekf on Jun 04, 2008 9:28 PM

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