17134) for Windows 10, a "Beta: Use Unicode UTF-8 for worldwide language support" checkbox appeared for setting the locale code page to UTF-8. This allows for calling "narrow" functions, including fopen and SetWindowTextA, with UTF-8 strings. However this is a system-wide setting and a program cannot assume it is set. In May 2019, Microsoft added the ability for a program to set the code page to UTF-8 itself, allowing programs written to use UTF-8 to be run by non-expert users. In Windows 11 some system files are required to use UTF-8 and do not require a Byte Order Mark. Notepad can now recognize UTF-8 without the Byte Order Mark, and can be told to write UTF-8 without a Byte Order Mark. Some other Microsoft products are using UTF-8 internally, including Visual Studio and their SQL Server 2019, with Microsoft claiming 35% speed increase from use of UTF-8, and "nearly 50% reduction in storage requirements." Programming platforms Microsoft's compilers often fail at producing UTF-8 string constants from UTF-8 source files. The most reliable method is to turn off UNICODE, not mark the input file as being UTF-8 (i.e. do not use a BOM), and arrange the string constants to have the UTF-8 bytes. If a BOM was added, a Microsoft compiler will interpret the strings as UTF-8, convert them to UTF-16, then convert them back into the current locale, thus destroying the UTF-8. Without a BOM and using a single-byte locale, Microsoft compilers will leave the bytes in a quoted string unchanged. On modern systems setting the code page to UTF-8 helps considerably, but invalid byte sequences are still not preserved (using can work around this). See also Bush hid the facts, a text encoding mojibake Notes References External links Unicode Microsoft Windows