"Drag and drop" is a common method of moving files between folders and disk devices. When this doesn't work as expected, the problem is likely to reside on the target device.
Drag and Drop Explained
One of the most basic and common file management tasks in Windows 7 is to drag a file into a new location. This might be to or from the desktop or between your computer and an external device (such as an MP3 player); it might even be from your Windows 7 desktop to the desktop of a virtual machine.
Drag and drop is a popular feature of the Windows GUI, so when this doesn’t work it can prove frustrating.
There are various reasons why a computer won’t allow you to drag files from folder to folder or device to device. These usually relate to permissions and disk space.
Dragging Files to a Device or Folder
In most cases, dragging one or more files to a device should be pretty straightforward and can be done in a number of different ways.
For instance the most common way is to open the source folder on your PC or laptop (where you’re copying from) and to also open the target folder (a folder on the device you’re copying to) and then with both folders visible drag the data from one to the other, holding SHIFT as you do so to change the default copy mode to Move.
Another way of doing this is to simply drag the data from the source folder and drop it on the drive letter of the device you’re moving it to, or even to right-click the selected files or folder and select Send to > [DEVICENAME].
Why Won't My Computer Let Me Drag Files?
If you find that your computer won’t let you drag files from one location to another, the problem might be related to either permissions on the target device or disk space.
For instance you might be attempting to copy files to a folder that is somehow write-protected. Many Flash memory cards can be write-protected, so dragging and dropping files and folders to these types of device can only be performed when the card is suitably configured. You can usually do this by looking for a small sliding tab on the edge of the card, and noting its two positions.
Meanwhile if the target device is full then you will be unable to add more files to it. If the target device is almost full and your intended file or folder is too large (or very close to the difference) then you may still experience problems. Check the file size of the folder or files you are copying (this is displayed in the bottom of Windows Explorer when a file is selected) and check the space on your target device (right-click > Properties) to find out if the data you’re copying will fit.
Finally, one other reason that you might be unable to drag files is because you’re using a view that doesn’t permit this. For instance, you might be observing a file directory structure via Internet Explorer, possibly on an FTP site. As such dragging and dropping folders would not be possible unless explicitly permitted.
Source: Author experience
Images: Screenshots by author