# File modification time
**URL:** https://community.mp3tag.de/t/file-modification-time/2188
**Category:** Support
**Created:** [August 13, 2005, 7:54pm UTC](https://community.mp3tag.de/t/file-modification-time/2188 "2005-08-13T19:54:56Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@JJ\_Johnson](https://community.mp3tag.de/u/JJ_Johnson)
#### Post date: [August 13, 2005, 7:54pm UTC](https://community.mp3tag.de/t/file-modification-time/2188/1 "2005-08-13T19:54:56Z")
I recently moved my music collection from a local hard drive on Windows XP to a networked attached storage device. The device is a ReadyNAS 600, the OS of which is based on some variant of Linux.
In Mp3tag I have 'Preserve file modification time when saving tags' unchecked. When operating on files on a local drive the modification times are updated correctly, but they're not being updated at all on the NAS.
Any ideas of why this would be? When I use another program, say Notepad to edit a text file, then the file modification is updated on the NAS.
When the above option is disabled does Mp3tag do anything explicit to change the modification time, or is up to the operating system? How does Mp3tag preserve the modification time when this option is enabled?
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### Author:  [@Sebastian\_Mares](https://community.mp3tag.de/u/Sebastian_Mares)
#### Post date: [August 14, 2005, 5:56am UTC](https://community.mp3tag.de/t/file-modification-time/2188/2 "2005-08-14T05:56:01Z")
> [@](#):
>
> How does Mp3tag preserve the modification time when this option is enabled?
>
> \<{POST\_SNAPBACK}\>
It's a flag in the FAT as far as I know. If it doesn't work try to "touch" the files.
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### Author:  [@JJ\_Johnson](https://community.mp3tag.de/u/JJ_Johnson)
#### Post date: [August 14, 2005, 6:21am UTC](https://community.mp3tag.de/t/file-modification-time/2188/3 "2005-08-14T06:21:47Z")
> [@](#):
>
> It's a flag in the FAT as far as I know. If it doesn't work try to "touch" the files.
I may try touch.
What is the FAT?
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### Author:  [@Sebastian\_Mares](https://community.mp3tag.de/u/Sebastian_Mares)
#### Post date: [August 14, 2005, 6:33am UTC](https://community.mp3tag.de/t/file-modification-time/2188/4 "2005-08-14T06:33:17Z")
It's the file allocation table which AFAIK also contains information about attributes like read-only, archived... For NTFS, there is no FAT but MFT (Master File Table).
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### Author:  [@JJ\_Johnson](https://community.mp3tag.de/u/JJ_Johnson)
#### Post date: [August 14, 2005, 6:48am UTC](https://community.mp3tag.de/t/file-modification-time/2188/5 "2005-08-14T06:48:33Z")
> [@](#):
>
> It's the file allocation table which AFAIK also contains information about attributes like read-only, archived... For NTFS, there is no FAT but MFT (Master File Table).
>
> \<{POST\_SNAPBACK}\>
Ok, but I don't get what you mean about a flag. Are you talking about an 'archive' flag? I'm talking about the modification date/time.
What I'm asking is how is whether Mp3tag normally does anything other than simply open the file, write to it, then close it whenever 'Preserve modification time' is not set. And what it does to preserve the time when that option _is_ set.
The file system on the NAS is ext3 under Linux and Windows uses CIFS to access it across the network.
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### Author:  [@Sebastian\_Mares](https://community.mp3tag.de/u/Sebastian_Mares)
#### Post date: [August 14, 2005, 7:54am UTC](https://community.mp3tag.de/t/file-modification-time/2188/6 "2005-08-14T07:54:51Z")
> [@](#):
>
> Ok, but I don't get what you mean about a flag. Are you talking about an 'archive' flag? I'm talking about the modification date/time.
>
> \<{POST\_SNAPBACK}\>
The modification time is also stored in the FAT/MFT as time stamp.
I guess that MP3Tag uses the SetFileTime API from kernel32.dll to mess with that time stamp.
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### Author:  [@system](https://community.mp3tag.de/u/system)
#### Post date: [February 9, 2026, 12:19pm UTC](https://community.mp3tag.de/t/file-modification-time/2188/7 "2026-02-09T12:19:26Z")