Error: MAXQDA can't open the chosen file.

When you see the error message, "MAXQDA can't open the chosen file. The file may be already opened, or it has the wrong file format, or it may be broken. "

 the error message usually appears if 

• the project file is already opened, i.e. the project file is already open in MAXQDA, maybe the window is in the background, the user forgot and tries to open the file a second time, please check all the background processes
• the project file is damaged 
• the user tries to open a file with a wrong file format (e.g. an older MAXQDA version that can not be converted or even a file that is not in .mx format like a .docx file e.g.)