Whenever you try to play a video (MP4 or others), you may get this error;
We can’t get to the file for this item. If it’s downloading or just finished downloading, try again soon. Otherwise, make sure another app isn’t using the file and that you can access the place the file is stored.
Here’s how you can fix it;
Open file explorer by clicking Windows Start or Search;
Right-click the folder that contains those files giving you error and select properties;
Next, click the “Security” tab and click “Edit” button to continue;
Click “Add” button to continue;
Next, click “Advanced” button;
Click “Find Now” in the next screen to select your own specific username via which you are logged in. For example, in my case, it is “blue sky”. Select that username and click “OK” button to continue;
Press “OK” in the next screen;
Next, click your own username from the list and check-mark the box “Full control” permissions. Click “Apply” button when done;
In the final screen, click the “OK” button to finish setting up folder permissions;
Now, you should be able to play any video without any error in that folder for which you recently granted permission.