Android 6: Can't save text files to external sd card I can open text file from external sd card, but I can't save it back to the same place because of error 


  can't create storage...
  Permision denied


Is there a way to change app permission to saving files to external sd?
To write to an external drive you need to add the necessary permissions to your manifest. To write you will want to add: 

&lt;uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /&gt; 

To read from the drive you should add: 

&lt;uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /&gt;

You should be able to get away without the read permission but if you want to futureproof your app and make it so users don't run into bugs add it in. Google's API explains the proper guidelines for handling datafiles here.