OneDrive for Business file server migration misses files for executive data: Fix Guide

When migrating files from a file server to OneDrive for Business, you may discover that certain files are missing after the migration completes. This problem often affects executive data, including files with restricted permissions, long paths, or special characters in file names. The issue typically occurs because the migration tool skips files that violate OneDrive or SharePoint sync constraints. This guide explains why executive data gets skipped and provides step-by-step fixes to locate and migrate those missing files.

Why the Migration Skips Executive Files

The SharePoint Migration Tool (SPMT) and other migration utilities enforce the same file and folder naming rules that apply to OneDrive and SharePoint Online. Files that violate these rules are silently skipped. Executive data often resides in deeply nested folder structures, contains files with names longer than 400 characters, or uses characters such as ~ " # % & : < > ? / \ { | } that are blocked in OneDrive. Additionally, files with unique permissions inherited from the file server may not transfer correctly if the migration tool does not have sufficient access rights to read the file security descriptors.

Another common cause is the file size limit. OneDrive for Business allows files up to 250 GB per file. However, if the migration tool encounters a file that exceeds this limit, it fails silently. Executive data archives, large presentation files, or video recordings can trigger this limit. The migration log often marks these files as skipped without a detailed error message, making it difficult to identify the exact cause.

Finally, the migration tool may skip files that are locked by another process during the migration window. Executive workstations often have files open for extended periods, and the migration tool cannot copy open files. If the migration runs during business hours, these files are missed.

Steps to Find and Migrate Missing Executive Files

1. Run a pre-scan with SPMT to identify blocked files
   Open the SharePoint Migration Tool and select Start fresh. Choose the file server source and OneDrive destination. Before starting the migration, click Scan. The scan report lists every file that will be skipped and the reason. Export this report as a CSV file for reference.
2. Check the migration task report for skipped items
   After the migration finishes, open SPMT and go to Task status. Select the completed task and click View report. Look for rows with a status of Skipped or Failed. The report includes the file path and the error code.
3. Fix file name and path issues before retrying
   Rename files that contain blocked characters. Shorten file paths to fewer than 400 characters by moving files to a shallower folder structure. Remove leading or trailing spaces in file names. After fixing, run the migration again for only the affected folders.
4. Resolve permission conflicts with a super-user account
   Use a migration account that has Full Control on the file server source. If executive files have unique permissions, grant the migration account explicit Read and Write permissions on each affected folder. In SPMT, set the user mapping to preserve the original file owner or reassign to the executive user.
5. Use PowerShell to compare source and destination file counts
   Open SharePoint Online Management Shell. Run Get-PnPFilesInFolder -FolderSiteRelativeUrl "Documents/Executive" -Connection $conn | Measure-Object to count files in the OneDrive destination. Compare that count to the file server folder count. If the numbers differ, identify missing files by running a recursive comparison script.
6. Migrate locked files after hours
   Schedule the migration to run outside business hours. Use the Schedule option in SPMT to set a start time. Alternatively, use the Start-SPFileMigration PowerShell cmdlet with the -StartTime parameter to specify a time when files are not in use.

If Executive Files Still Have Issues After the Main Fix

OneDrive reports a 404 error for a migrated executive file

A 404 error means the file exists on the file server but was not uploaded to OneDrive. This occurs when the file name contains a URL-unsafe character that the migration tool fails to encode. Open the file server folder, rename the file to remove characters such as & or #, and run the migration again on that specific folder. Use the SPMT incremental migration option to only upload new or changed files.

Executive files appear in OneDrive but cannot be opened

If the file is present but shows an error when opening, the file may have corrupted during transfer. This often happens with very large files over 10 GB. Download the original file from the file server, verify its integrity by opening it locally, then upload it manually using the OneDrive web interface. Do not use the migration tool for files that fail this way.

Permission inheritance breaks after migration

OneDrive for Business does not support the same NTFS permission model as a file server. After migration, all files in a OneDrive folder inherit permissions from the parent folder. If executive files require unique permissions, you must set them individually in OneDrive. Use the Manage access option on each file to grant specific user permissions. Alternatively, create a separate OneDrive library for executive data and apply permissions at the library level.

SharePoint Migration Tool vs Manual Upload for Executive Data: Key Differences

Item	SharePoint Migration Tool (SPMT)	Manual upload via OneDrive web
File size limit	250 GB per file	250 GB per file
Path length limit	400 characters	400 characters
Blocked characters	Skips files with blocked characters	Blocks upload with clear error message
Permission handling	May skip files without explicit migration account access	Uploader must have write permission on destination
Locked file behavior	Skips open files silently	Fails with file-in-use error
Incremental migration	Supported	Not supported

For executive data, SPMT is the preferred method for bulk migration because it supports incremental runs and generates detailed logs. Manual upload is better for individual files that SPMT consistently skips due to path or character issues.

You can now identify why executive files are missing after a file server migration and apply targeted fixes for path length, character, permission, and locked file issues. Next, review the SPMT pre-scan report for all remaining folders to catch similar problems before the next migration wave. For ongoing executive data management, consider setting up a OneDrive sync policy that excludes blocked file types and enforces naming rules at the source.