There is an answer to this problem in frequently asked questions, but no matter what I tried, the problem was not solved. I set the location to another country in the region and language settings. I turned the computer off and on. Then I turned it back to Turkey and started over. It didn't happen again. I changed all of the Keyboard Language Region settings. Didn't do that again. I am using 64 bit ide. This error started after Windows update updated Net framework. I cannot save files using Turkish characters or open files with Turkish characters.