ICS Issues and Insider Preview Builds

If you are part of the Windows Insiders program and use ICS (Internet Connection Sharing) you may have noticed issues in recent builds.  I utilize ICS at work daily to share the connection with a laptop.  My main workstation has been running Insider Preview builds from the Fast ring since last Spring.  Overall it has been stable (save for issues with some Apps here and there which I discussed in my last post).

I noticed on Build 14295 that ICS suddenly stopped working.  The existing connection would connect but there was no internet. Trying to troubleshoot and remove and setup the virtual connection would eventually lead to errors such as “Internet Connection Sharing cannot be enabled”.

I perused several forums and found suggestions pointing to services that should be running and driver update suggestions but nothing worked in my case.  A user on the Microsoft Support forums mentioned that the file hnetcfg.dll showed up in his error log and that by copying an older version over into the Windows/System32 folder his ICS functionality returned.

Sure enough, I debugged the error in Visual Studio I was receiving and the error referenced hnetcfg.dll several times.

On my system I still had Build 14279 installed as I had rolled back once I saw that Build 14295 had issues with ICS.  Yesterday with Build 14316 released, I updated, encountered the same issue and after identifying the hnetfcfg.dll as a possible fix I found the 14279 version in the Windows.old/Windows/System32 folder.  I copied that into the current installation Windows/System32 folder and all is well again.

Here is a link to hnetcfg.dll version 10.0.14279.1000 if you need it to test your installation. Just download and unzip.