My client has a problem with opening .pptx files (v.2010). They opens as .zip files. I have found information about this same problem regarding v.2007 files. But that is not the problem here. .pptx files in 2007 format opens fine. I have tried to change the mime-types, but that doesnt help. It works fine in firefox, but not in IE 8. (the client is restricted to use IE 8).The site is running on Episerver CMS 4, but is going to upgrade to CMS 6 in a short while. Is it possible that this will be fixed when they upgrade their CMS?
If adding the MIME types don't help, you may have to install the MS Office Compatibility Pack on your server. Read more about it in this blog post:
Thank you for your answer! I was hpoing not to install that compability pack. Office is not installed on the server. Do I then have to install Office aswell?
Is it a chance that this will be easier when the CMS is upgraded to CMS 6?
No, you don't have to install Office on the server, just the compatibility pack.
This is likely a server problem and not something that will be fixed by upgrading EPiServer CMS.
You can also add the MIME-types programatically, as stated in this blog comment: http://www.epinova.no/en/blog/Lars-Oyvind-Bodahl/dates/2009/12/office-2007-files-behaves-as-compressed-folder/#comment516 but that would not be my first choice because you'd need to recompile and redeploy if there are any changes to the MIME mapping.
If this is an environment where all the users are restricted to the same IE version, you could get the network admin to roll out a setting which forces IE to use default MIME handling instead of trying to detect the file type:
Thank you so much for the help. Then I will ask them to try to roll out the setting in IE before we try to install the Office Compatibility pack.