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I am trying to deploy a Silverlight app to iis on a Win 2003 server. I add the mime type for silverlight to iis ( .xap, application/x-silverlight-app ) and then restart the app pool, and the app downoads and runs.

However, running an iisreset or restaring the machine blows away the mime entry. Why does this happen?

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Did you do this via IIS MMC? – Kev Jan 27 '12 at 18:34
yes, right click on machine name under iis > properties > mime types – Roger Guess Jan 27 '12 at 18:49
Does it physically get removed from the list or just stops working? – Kev Jan 27 '12 at 18:59
both (these are extra characters because of the min requred to comment) – Roger Guess Jan 27 '12 at 19:14
up vote 1 down vote accepted

You shouldn't be using IISReset.

IISReset has a /NOFORCE parameter that waits for the service to shut down cleanly before restarting it.

That might get you around the loss of settings when the service fails to write out the metabase.xml file in time (perhaps due to antivirus interference; it's often something that doesn't reproduce elsewhere when this happens).

But rule-of-thumb, don't use it.

I can't think of any situations other than complete failure of all hosted websites simultaneously in which IISReset might actually be required.

Most of the time, you can get what you need to do done with a Recycle of the relevant Application Pool. Note: It doesn't actually start a new process until the next request comes in, unless requests are queued already.

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Add the mime type value to the server configuration file in:


In your case:

     <mimeMap fileExtension=".xap" mimeType="application/x-silverlight-app" />

That will not get removed during an iisreset.

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