File Load Some bytes have been replaced with the Unicode substitution character while loading file

Question

I was debugging in the .Net framework source code suddenly when I stepped into a file of theirs, visual studio 2010 raised this error:

File Load:
Some bytes have been replaced with the Unicode substitution character while loading file XXX, Saving the file will not preserve the original file contents.

when I click OK, the file is marked as unsaved, and when you try to save it, it says that the file is locked, but I can overwrite the file. I don't know what does this message means.

And why now, not the first time when visual studio downloaded the file from Symbol server?

Answer 1

I started to get this error after switching on (for test purposes) the new setting "Beta: Use Unicode UTF-8 for worldwide language support" in the recent Windows 10 Spring 2018 update.

The message would then appear for every file that has non-ascii characters (German Umlauts mostly in my case) and had not been stored as UTF8 before.

Short-time fix: Revert the setting to not use UTF-8 as the "Current language for non-unicode programs", but use a language with the special characters that are used in the source files.

Long-time fix: Convert all your soure files to UTF-8.

Answer 2

I fixed this issue by changing my "Language for non-Unicode programs" setting to "English (United States)". If you are using Windows 10, you can find it in "Control Panel -> Clock, Language, and Region -> Region -> Administrative".