Hello

The Data Usage and Metered Connection settings are missing from my Windows 8.1

I agree that this might be due to installation of some application, but finding it is almost impossible.

Any guesses how can I fix this?

Hi Matig Manougian,

Can we get the settings before ?
Where did you get the settings ?
Usually we can get the settings here .
Win+I >PC Settigns>Network>Choose the connection name  and left click it .

We also can run "dism /online /cleanup-image /restorehealth" to check the health of the system files.
If we suspect there is a third party conflicts here ,we can try to perform a clean boot to have a troubleshoot .
How to perform a clean boot in Windows
https://support.microsoft.com/en-us/kb/929135?wa=wsignin1.0

If the issue occurred recently ,we can perform a system restore to recover the machine to a previous normal point .

Best regards