ARCHIVED: Why can't I create files or folders in my root directory on my Windows computer?

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Note: UITS recommends that you use a current version of Windows on computers connected to the Indiana University network; see Recommended Windows operating systems at IU.

On any computer running Windows on a FAT16 partition, you may occasionally get one of the following messages:

Cannot make directory entry - 'filename.'

'filename': This filename is not valid.

Unable to create 'New Folder'. Make sure the disk is not full or
read-only.

This is due to a limitation in FAT16, an older file system: There is a limit of 512 entries in the root directory. It doesn't matter if you still have a great deal of disk space free on the hard drive, the root directory can have a maximum of only 512 files. (This applies only to Windows 95, 98, Me, and NT 4.0, which can be installed on FAT16 partitions.)

If you are using FAT16, you might get one of the error messages above even if you do not have 512 files and/or folders in your root directory. This is a problem that is caused by the way Windows handles long filenames. MS-DOS uses one directory entry for each file and/or folder. Windows, however, uses additional directory entries to store long filenames and folder names, and the associated 8.3 aliases, which are the shortened, DOS-compatible versions of long filenames. This means that you can run out of directory entries with fewer than 512 files or folders in the root directory.

Use the following steps to free root directory entries:

  • Check the drive for invalid long filenames, and then defragment the drive. Double-click My Computer, click the correct drive, and then click Properties. Click the Tools tab, and then click Check Now. Perform the default correction if invalid long filenames are found. Then choose Defragment Now.
  • Rename any files or folders in the root directory using only uppercase 8.3-compliant file or folder names. The characters that are valid for an 8.3-compliant file or folder name include any combination of letters (A-Z) and/or numbers (0-9), plus the following special characters:
    ~ Tilde
    ` Opening single quotation mark
    ! Exclamation point
    @ At sign
    # Number sign
    $ Dollar sign
    ^ Caret
    & Ampersand
    % Percent sign
    ' Apostrophe
    - Hyphen
    _ Underscore
    { Left brace
    } Right brace
    ( Opening parenthesis
    ) Closing parenthesis

This is document aekm in the Knowledge Base.
Last modified on 2018-01-18 12:22:06.