Migrated Files Lose Modified Dates: OneDrive for Business Fix

When you migrate files into OneDrive for Business using a third-party tool or a manual copy-paste operation, the original modified dates often change to the migration date. This behavior breaks file version tracking, confuses team members who rely on timestamps, and can cause audit compliance issues. The root cause is that the migration process or the copy method does not preserve the last-modified timestamp stored in the file system metadata. This article explains why modified dates are lost, provides a reliable step-by-step fix using Windows built-in tools and PowerShell, and shows you how to verify the dates are correctly preserved.

Why Migrated OneDrive Files Lose Their Original Modified Dates

When you drag and drop files from an external drive or use a migration tool that does not explicitly copy file timestamps, Windows assigns the current date and time as the new modified date. OneDrive for Business syncs the file to the cloud and then propagates this new timestamp to all synced devices. The original modified date is permanently overwritten because the file system sees the copy operation as a new file creation event.

The OneDrive sync client itself does not alter timestamps during a normal upload. The problem originates from the method you use to get the files into the OneDrive folder. Common culprits include:

• Using File Explorer drag-and-drop from a network drive or external hard drive
• Using a third-party migration tool that does not include timestamp preservation in its feature set
• Using the OneDrive web browser upload interface, which always sets the modified date to the upload time

The fix requires using a command-line tool that is designed to copy file metadata, specifically the last-modified timestamp, and then placing those files inside the local OneDrive folder so the sync client uploads them with the correct dates.

Steps to Restore Original Modified Dates on Migrated OneDrive Files

The following method uses the robocopy command, which is built into Windows 10 and Windows 11. It copies files from your source location to your local OneDrive folder while preserving all timestamps. After the copy completes, OneDrive syncs the files to the cloud without changing the dates.

1. Open Windows PowerShell or Command Prompt as Administrator
   Press the Windows key, type PowerShell, right-click Windows PowerShell, and select Run as administrator. Click Yes if prompted by User Account Control.
2. Identify the source folder path
   Open File Explorer and navigate to the folder that contains your original migrated files. Click the address bar and copy the full path. For example: D:\MigrationBackup\ProjectFiles
3. Identify your local OneDrive folder path
   In File Explorer, locate your OneDrive folder. The default path is C:\Users\YourUserName\OneDrive - YourCompanyName. Click the address bar and copy the full path.
4. Run the robocopy command with timestamp preservation flags
   In the PowerShell window, type the following command and press Enter:
   robocopy "D:\MigrationBackup\ProjectFiles" "C:\Users\YourUserName\OneDrive - YourCompanyName\ProjectFiles" /E /COPY:DATSO /DCOPY:T /R:3 /W:5
   Replace the source and destination paths with your actual folders. The /E flag copies all subfolders including empty ones. The /COPY:DATSO flag copies Data, Attributes, Timestamps, Security (NTFS permissions), and Ownership. The /DCOPY:T flag copies folder timestamps.
5. Wait for robocopy to complete and review the log
   robocopy will display a summary showing the number of files copied, skipped, and any errors. Verify that the Files Copied count matches your expectations. If you see errors, note the file paths and check for permissions or path length issues.
6. Allow OneDrive to sync the new files
   Open the OneDrive sync client by clicking the OneDrive cloud icon in the system tray. The sync process will start automatically. Wait for the status to show Up to date.
7. Verify the modified dates in OneDrive online
   Open a web browser, go to onedrive.live.com, and sign in with your work or school account. Navigate to the folder you just copied. Right-click a file and select Details. The Modified date should match the original timestamp from your source folder.

If OneDrive Still Shows the Wrong Modified Dates After Migration

OneDrive Updated the Timestamp After Sync

If you verified the local files have the correct timestamps but OneDrive online still shows the migration date, the sync client may have already uploaded the files before you ran robocopy. In this case, delete the files from OneDrive online, then re-run the robocopy command to the same local folder. OneDrive will re-upload the files with the preserved timestamps.

robocopy Shows Access Denied Errors for Some Files

If robocopy reports access denied errors, the source files may have restrictive NTFS permissions. Run the command with the /B flag to copy in backup mode, which bypasses file permissions. The full command becomes:
robocopy "source" "destination" /E /COPY:DATSO /DCOPY:T /B /R:3 /W:5

Files Are Too Large or Paths Are Too Long for robocopy

robocopy supports long file paths natively in Windows 10 version 1607 and later. If you encounter Path Too Long errors, enable long path support in Windows Group Policy. Open Local Group Policy Editor, navigate to Computer Configuration > Administrative Templates > System > Filesystem, enable Enable Win32 long paths, and restart your computer. Then re-run the robocopy command.

Robocopy vs PowerShell Copy-Item for Timestamp Preservation

Item	Robocopy	PowerShell Copy-Item
Timestamp preservation	Preserves modified, created, and accessed timestamps with /COPY:DAT	Does not preserve timestamps by default; requires additional scripting
Folder timestamp preservation	Supported with /DCOPY:T	Not supported natively
Security and ownership	Copies NTFS permissions and ownership with /COPY:DATSO	Does not copy security or ownership
Resume capability on failure	Built-in with /Z or /B flags	Not built-in; requires custom error handling
Best use case	Large migrations with many files and subfolders	Simple single-file copy where timestamps are not critical

You now have a working method to migrate files into OneDrive for Business without losing modified dates. For future migrations, always use robocopy with the /COPY:DATSO and /DCOPY:T flags instead of drag-and-drop. To automate this process for recurring migrations, save the robocopy command as a batch file and schedule it with Task Scheduler. This approach ensures your file timestamps remain accurate for version tracking and compliance audits.