Hi JESSAN,
It is most likely that you have the file open in another program or another instance of MATLAB.
Alternatively, there is a chance that the file permissions were changed on the system level. So you can try changing that manually. For this, the method depends on your operating system, e.g. chmod for linux.
For Windows, right click on the file and check the properties option and see if it is manually marked Read-Only and if so if it can be unchecked or not.
Thank you,
Rishav Saha
