SOLVED: Why the DATE MODIFIED Metadata Changes on Some Copied Files But Not Others

We recently had a client who was used to copying files from one folder to another on their server via a file share from their desktop and not see the date modified information change on those files. However we recently migrated them to a new server and now whenever they copy files from one folder to another, the date modified field is updated to the date and time the files were copied. They don’t like that and wanted an explanation. This is what we told them.

This is a very complex and confusing topic for most people (including many techs) that boils down to date modified metadata is not something that can be relied on only as an indication that the file CONTENTS have been changed but rather something has changed ON the file.

These five items can effect the DATA MODIFED meta data:

1. if the files are being moved or copied
2. if the files are being moved between older operating systems and newer ones (i.e. Windows 7 to Windows Server 2022)
3. if the files are being worked on directly on server (i.e RDP, locally) or if you’re working from a drive share
4. if the files being copied onto the same disk volume or to a different disk on the same server
5. If the files being copied were already copied at least once in the past on the server

The Date Modified metadata that is displayed in the Windows Explorer typically does not change when moving or copying a file on the SAME DRIVE. If files are copied or moved to a different drive (i.e. on the same server or even between PC and Server), the Date Modified can change.

The strangest part of our testing found that if the file being copied has ALREADY been copied once on the server, the date modified does not change but the first time the file is copied when it is on a file share the date modified does change.

You can see this in the screenshot above. The original file was created 2024-06-06 and 10:10am. For testing purposes we COPIED THE COPIES several more times and found, their dates modified did not change.

Microsoft explains it as follows:

This behavior can occur due to differences in how file metadata is handled between local file systems and network shares:

1. Initial Copy via Network Share: When you copy a file for the first time via a network share, the “Date Modified” attribute might change to the current date and time. This is often due to how the network protocol handles file metadata during the transfer.
2. Subsequent Copies on the Server: Once the file is on the server, subsequent copies within the same drive or volume typically preserve the “Date Modified” attribute. This is because the file system on the server handles metadata more consistently.

All this means, the DATA MODIFIED changes you reported will occur less often, the more you use the server.

---