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In Windows Server 2003, in the "Attributes" column of windows explorer, some files have "A" or "C" or "AC" or others. What do these mean?

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Another question is "What the hell does the Archive flag do" - I've seen it since the early days of MS-DOS, it's applied to almost every single file, and I've never had a need/reason to change it, but at the same time never had any idea what it does. Is it still functional? – Mark Henderson Jul 2 '09 at 0:33
@Mark: to my knowledge, the Archive flag was used by backup utilities. It was reset after the backup was done. If you modify the file, it is set again, to mark it must be back up again. Primitive, so no more used, I guess. – PhiLho May 12 '11 at 11:07
The archive bit is still used. I wrote a program to reset permissions on all of our users' home directories if they were found to be out of whack. Changing permissions trips the archive bit. Really pissed off the operations people when the backups ran. – Patrick S. Nov 22 '11 at 0:43

10 Answers 10

up vote 27 down vote accepted

The others are:

L = Reparse Points
P = Sparse File
I = Not content indexed

I don't think I've ever seen the last two, but I do have files on my system that have the "N" designator which I don't recall ever seeing before Vista.

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I have seen the O attribute on the files I got after unzipping the Yii PHP framework archive (yii-1.1.7.r3135 to be precise). Not sure how it went there. Nor how to act on it... Noticed that because it has a specific icon overlay. – PhiLho May 12 '11 at 11:02

A = archive bit is set
C = compressed

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Another attribute is E for Encrypted.

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When Windows 7 "Backup and Restore" creates a "system image," it puts it in a root-level folder named WindowsImageBackup, which has the "I" attribute. Windows 7's "help attrib" command says:

C:\>help attrib
Displays or changes file attributes.

ATTRIB [+R | -R] [+A | -A ] [+S | -S] [+H | -H] [+I | -I]
       [drive:][path][filename] [/S [/D] [/L]]

  +   Sets an attribute.
  -   Clears an attribute.
  R   Read-only file attribute.
  A   Archive file attribute.
  S   System file attribute.
  H   Hidden file attribute.
  I   Not content indexed file attribute.
      Specifies a file or files for attrib to process.
  /S  Processes matching files in the current folder
      and all subfolders.
  /D  Processes folders as well.
  /L  Work on the attributes of the Symbolic Link versus
      the target of the Symbolic Link
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You can do more with Attributes.

CMD-RUN-Type (Hidden Command)

Attrib +h +s C:\Test\Testing

CMD-RUN-Type (Show Command)

Attrib -h -s C:\Test\Testing


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Others are as follows;

H = Hidden

S = System File

R = Read Only

AHS and R can be set by the user or system, as user you can use the 'attrib' command to add/remove attributes. C is a system only attribute.

To find out more about the attrib command goto a command window and type 'attrib /?'

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Backup software can clear the archive bit which is set when a file is modified. That way, it can be used to do incremental backups in order to skip over files that have already been backed up.

Since it can be set and unset at will, it's not necessarily the most reliable method and I think most backup software uses more sophisticated criteria for determining what to include in an incremental backup.

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I can tell you that the current version of BackupExec can use either the archive bit or the last modified timestamp for determining whether or not to back up a file. – joeqwerty Oct 23 '09 at 19:25

The A bit only shows up when you have backup software that sets it to indicate that file has been archived. When a user makes changes to a file, the operating system clears the archive bit, to indicate to the backup software that if it's doing an incremental or differential backup, it needs to backup that changed file and reset the A bit. Incremental backups reset the archive bit, so that the next incremental will only backup newly changed files. Differential backups do NOT reset the archive bit, so every differential backup grabs all the files that have changed since the previous full backup. So, to restore a system on Friday, an administrator would need the weekly backup from sunday and either the latest differential, or ALL the daily incrementals.

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You have this exactly backwards. The OS sets the archive bit when a file is created or modified. Backup software clears the archive bit when the file is backed up. – ThatGraemeGuy Mar 1 '11 at 7:16
Graeme is correct, the archive bit is set to indicate that the file needs to be archived, not that it has been archived. – John Gardeniers Mar 1 '11 at 10:46

I am looking at several subdirectories on a shared network drive that have an "I" attribute, and one shortcut to a subdirectory that also has an "L" ("HSDLI"). I am going to guess the "I" could mean Indexed, but I haven't a clue to what "L" might mean. I would guess it means Link, but looking at other shortcuts to individual files at least, they don't have that attribute letter, so that is probably not it.

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Not exactly useful as an answer if you're not sure of it. – TylerShads Oct 20 '11 at 13:04

D is missing from the above list so in case you're wondering like I was, D stands for "Directory." It's probably not included because the question focused on files, not directories, but I found this question in a search and had to continue my search to find out what D was, so, as a convenience to future readers, I added this answer.

Here's the link to the answer that included D:

Windows Explorers file attribute column values

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