cannot save to text file

[iamresearcher]

I have this program that extract a text file.

Later with the same program, I open this text file for reading and editing and then save what was edited.

But when I try to save it, the program tells the file is open. What could be the problem?

But when I delete this extracted text file and replace it manually with my backup same text file for the same purpose, I can save successfully.

I guess the text file is extracted in somewhat way that cannot be used for editing and later for saving.

It must be noted that I have already tried to restart the computer and tried saving but still the program says the the file is already open.

The file is set to achive properties in windows.