The OS X Finder allows you to access and organize files and folders on your hard drive, with one common function being to move items to the trash. While you can drag items to the trash, an additional feature is to make a selection and then press the hotkey Command-delete, or choose "Move to Trash" from the File menu, which will place the selected items in your account's trash in preparation for deletion.
While this feature should work for files and folders in your account, sometimes it is not available for a selection, and the command in the system menus and corresponding hot key are grayed out and do not work.
This problem happens simply because your account does not have permission to edit at least one of the files or folders in your selection. In order to place a file in the trash you must have permissions settings for it that allow you to move it. At its basics, POSIX permissions settings may prevent your account from editing the file at hand, but alternatively you might have more advanced Access Control List entries, which in some complex setups may allow for the editing of files but prevent the moving of them around the file system, making the problem at hand seem a bit more obscure.
To address this problem, you will have to first locate the specific files that you are not able to delete, and then change the ownership and permissions settings for them. To do this, open the Terminal utility and perform the following steps:
- Type the following command, followed by a single space (do not press Enter yet):
sudo chmod -RN
- Drag the target file to the Terminal window, which will complete the full path to it so the command will target it. After doing this, the command should look like the following:
sudo chmod -RN /path/to/file
- Now press Enter, and supply your password when prompted.
- Repeat steps 1 through 3, but this time replace the "-RN" component of the command with "-R 666" so the command looks like the following:
sudo chmod -R 666 /path/to/file
When done, this procedure will have stripped out access control lists, and ensured the targeted file or folder tree is fully accessible by anyone for deletion. Now when you select the files in the Finder, you should be able to move them to the trash.
Beyond specific permissions settings, it is also possible your system is experiencing filesystem corruption, which can prevent the proper reading or alteration of permissions settings. This can prevent the system from properly storing and accessing file permissions, and result in similar inability to manage files in the Finder.
To help check for this, if the above Terminal commands do not work to make a file manageable, open Disk Utility (in the Applications > Utilities folder) and use it to check the drive containing the files in question for errors. If any are present, then repair the filesystem (to repair your boot drive, you will need to restart with the Command-R keys held to run Disk Utility from the recovery drive), and see if that clears the problem and allows you to select the files and replace them.