Win8 Metro Apps Fail Unless Enabling Loopback Exemption

Hello,

Need a heady group to assist with remediation; I want to troubleshoot and identify the root cause, then work toward a solution. Resetting, or any action that requires me to reinstall applications, cannot occur.

Symptoms:

Have a high end workstation running Win 8 Pro x64 w/ Media Center. None of the internet-enabled Metro applications work unless I exempt them using Fiddler or similar utility. No problem with desktop apps. Computer OS was a clean installation and never had a proxy server configured. There is no third party security software installed. Other Win 8 computers on subnet work properly.

Troubleshooting Steps (in order of execution):

• Verified video and network drivers are up-to-date. NIC card is an Intel 82579V gigabit adapter (embedded on motherboard).
• Disabled onboard NIC, installed Netgear gigabit adapter. Didn't fix, so went back to original NIC.
• Executed the following command to verify no proxy is configured: netsh winhttp show proxy.
  
  Results
  C:\WINDOWS\system32>netsh winhttp show proxy
  Current WinHTTP proxy settings:
  Direct access (no proxy server).
  C:\WINDOWS\system32>

• Excluded Store app, then uninstalled/reinstalled a couple of impacted apps. Still does not work.
• Verified all apps up to date.
• Excluded User app and created test Microsoft account. No help.
• Syncronized app licenses. No help.
• SFC /scannow reports no errors.

Conclusion:

For security reasons, I cannot leave apps excluded. Can someone help me repair app http configuration?

Anyone?

Same occurring in Windows 10 after upgrade frome Win 8.1

Did you ever figure out how to resolve this issue? Lots of people are having this problem in Windows 10, so if you did identify a fix and are willing to share it, many folks would be appreciative!