If you want to save a file with other encodings select save as and extend the save button in file dialog and select "Save with encoding". Or if you you want to get rid of this setting permanently just open File menu and select "Advanced save options" and there you should select "UTF-8 without signature" (and that also answered your last question :). Yes "UTF-8 without signature" is same as without BOM. https://stackoverflow.com/a/5411486

Advanced Save Options missing

There was File -> Advanced Save Options option in previous versions of Visual Studio. In 2017 RC this option's missed, therefore I don't see any in-app ways to get and change current file encoding.

You can also add it back to the File menu through Tools->Customize->Commands if you want to. https://developercommunity.visualstudio.com/content/problem/8290/file-advanced-save-options-option-is-missed.html