I’ve found that occasionally an application will fail to download to the SCCM cache and the folder is full of .tmp files.
Quite simply IIS7 is stopping the download and if you look at the W3SVC1 web logs on the Distribution Point you will see 404 errors in the log. Examine the file being downloaded when the error takes place, this will tell you which file type is being blocked. Since applications are deployed via HTTP, IIS7needs to be modified to allow these applications to download.
Open up the IIS Manager. Highlight the server node and double-click ‘Request Filtering’
Click the File Extension tab and choose a file extension that might be blocked by an application install. For example the .config file. Click ‘Remove’.
Confirm the removal.
Click ‘Allow File Extension’
Type in the file extension, in this instance .config, and click Ok.
Alternatively edit the applicationHost.config file located in the Windows\System32\inetsrv\config folder. Change any required file extensions to the value TRUE.
Repeat the process for further allowed file extensions. Restart IIS service post changes.
Double escaping could also be occurring. The IIS7 request filter rejects URLs containing + characters. So if you are pushing out Visual C++ Redistributable Packages for example then you will see the same symptoms in the cache folder.
In the Request Filtering section of IIS click the Rules tab and click ‘Edit Feature Settings’
Check ‘Allow Double Escaping’ and click Ok.
Restart the IIS service. You can use the iisreset command in DOS to do this.
Your software package will now start to deploy correctly to the SCCM cache folder.