OneDrive Migration Project Checklist for IT Admins

IT admins managing a OneDrive migration project often face challenges with data loss, sync failures, and permission errors. These problems stem from incomplete planning, incorrect tool selection, or missing pre-migration steps. This article provides a complete checklist covering pre-migration preparation, migration execution, and post-migration verification to ensure a smooth transition for your organization.

Why OneDrive Migration Projects Fail and How to Prevent It

OneDrive migrations fail most often due to three root causes: insufficient user data inventory, incorrect permission mapping, and lack of a rollback plan. IT admins often underestimate the number of files, the size of the data, or the complexity of sharing links. Without a proper audit, you risk moving orphaned files or breaking shared access. This section explains the technical and procedural requirements you must address before starting any migration.

Understanding OneDrive Storage Limits and File Types

Each OneDrive for Business account provides 1 TB of storage per user by default. Tenant admins can increase this limit up to 5 TB per user through the SharePoint admin center. File size limits are 250 GB per file. OneDrive does not support file names longer than 400 characters or paths longer than 400 characters. It also blocks syncing of specific file types like .exe, .dll, and .scr. You must identify and rename or exclude blocked items before migration.

Prerequisites for Your Migration Tool

Microsoft offers three migration tools: the SharePoint Migration Tool (SPMT), the Migration Manager in the Microsoft 365 admin center, and third-party tools like ShareGate or Mover (now part of Microsoft). Each tool requires that you have Global admin or SharePoint admin permissions. You also need to enable the migration service in the admin center. For SPMT, install the tool on a Windows 10 or Windows 11 machine with at least 8 GB of RAM and 10 GB of free disk space.

Complete Pre-Migration Checklist

This checklist covers tasks you must complete before moving any files. Skipping any step can cause data loss or sync errors.

1. Audit all user data sources
   Inventory all locations where user files reside: local folders, network shares, Google Drive, Dropbox, or legacy on-premises servers. Document the total size, file count, and folder structure.
2. Check OneDrive licensing for every user
   In the Microsoft 365 admin center, go to Users > Active users. Verify each user has a OneDrive for Business plan assigned. Users without licenses cannot receive migrated data.
3. Identify blocked or unsupported file types
   Run a scan using SPMT or a PowerShell script to find files with extensions that OneDrive blocks. Common blocked types include .exe, .dll, .scr, .vbs, .js, and .ps1. Create a plan to exclude, rename, or archive these files.
4. Resolve file name and path length issues
   Find files with names longer than 400 characters or paths longer than 400 characters. Shorten names or move files closer to the root of the folder structure.
5. Document existing sharing permissions
   Export current sharing links and permissions from the source system. OneDrive migration tools do not always preserve external sharing links. You may need to re-share files after migration.
6. Set OneDrive storage quota for each user
   In the SharePoint admin center, go to Policies > Storage. Adjust the default OneDrive storage limit if users will need more than 1 TB. Set a quota that matches each user’s audited data size plus 20 percent buffer.
7. Communicate the migration plan to users
   Send an email at least two weeks before the migration. Instruct users to clean up old files, delete duplicates, and unlink their current OneDrive account from any PC using OneDrive settings > Account > Unlink this PC.
8. Perform a pilot migration with a test user group
   Select 5 to 10 users with typical data sizes. Run the migration for this group first. Verify file integrity, permissions, and sync behavior before expanding to the full organization.

Step-by-Step Migration Execution

Follow these steps to run the migration using the Microsoft Migration Manager. The same logic applies to other tools with minor interface differences.

1. Open the Migration Manager in the Microsoft 365 admin center
   Go to Admin centers > SharePoint > Migration. Select Migration Manager from the left menu. This tool supports bulk migrations from network shares, Google Drive, Dropbox, and Box.
2. Create a migration task and select the source
   Click Add task. Choose your source type: File share, Google Drive, Dropbox, or Box. Enter the source path and authentication credentials. For network shares, use the UNC path format.
3. Map source folders to target OneDrive accounts
   In the mapping step, specify which source folder maps to which user’s OneDrive. You can use a CSV file with columns for source path and target user principal name (UPN). The tool creates the target folder structure automatically.
4. Set migration settings
   Choose to preserve file modified dates, created dates, and permissions. Enable incremental migration if you plan to run multiple passes. Leave the default setting to skip files that already exist in the target.
5. Start the migration
   Click Start. The tool begins copying files. Monitor the progress in the Migration Manager dashboard. Expect slower speeds for large numbers of small files. A typical migration moves 1 to 5 TB per 24 hours depending on network bandwidth and file count.
6. Run an incremental pass for changed files
   After the initial full migration, run a second pass to copy any files that changed during the first pass. This reduces the final cutover window. Schedule the incremental pass 24 to 48 hours before the cutover date.
7. Perform the final cutover
   On cutover day, stop access to the source system. Run one final incremental migration. Verify all user files are present in OneDrive. Then redirect users to access OneDrive.

Post-Migration Verification and Common Issues

After the migration completes, verify that data integrity and permissions are intact. Address common issues quickly to avoid user frustration.

Users Cannot See Their Files in OneDrive

This usually happens when the migration target was incorrect. Check the mapping CSV file for typos in the user principal name. Use the Migration Manager report to see which files failed and why. Re-run the migration for the affected users after correcting the mapping.

Shared Links Are Broken After Migration

OneDrive migration tools do not migrate external sharing links. Users must re-share files with external collaborators. To minimize disruption, provide a list of previously shared files to each user. Instruct them to create new sharing links from OneDrive.

Sync Client Shows Errors After Migration

If users had the old OneDrive sync client linked to a different account, they must unlink and re-link. Have users open OneDrive settings, go to Account, click Unlink this PC, then sign in with their new OneDrive account. This resolves most sync errors.

Files Are Missing or Corrupted

Run a file integrity check using the Migration Manager report. The report lists every file with its status: Success, Warning, or Failed. For failed files, check the error message. Common causes include file name length limits, blocked file types, or insufficient target storage quota. Resolve the issue and re-run the migration for those files only.

Migration Tools Comparison: Microsoft Native vs Third-Party

Item	Microsoft Migration Manager / SPMT	Third-Party Tools (ShareGate, AvePoint, etc.)
Cost	Free with Microsoft 365 subscription	Licensed per user or per TB; varies by vendor
Source support	File shares, Google Drive, Dropbox, Box	File shares, Google Drive, Dropbox, Box, legacy on-premises SharePoint, and more
Permission mapping	Basic permission preservation for files	Advanced permission mapping including group memberships and site-level permissions
Incremental migration	Yes, built-in	Yes, with delta detection
Reporting	Built-in dashboard with CSV export	Detailed reports with drill-down per file and per user
Speed	Moderate; limited by Microsoft throttling	Faster with parallel processing and throttling avoidance

Use the native tools for simple migrations with fewer than 500 users and standard file shares. Use third-party tools for complex migrations involving multiple source types, granular permission mapping, or tight deadlines.

With this checklist, you can now plan, execute, and verify a OneDrive migration for your organization. Start with the pre-migration audit and pilot test before moving all users. After migration, use the Migration Manager reports to confirm data integrity. For large enterprises, consider third-party tools to reduce migration time and improve permission accuracy.