How to migrate office files from an old server without downtime

Summary

This guide helps you troubleshoot and resolve: How to migrate office files from an old server without downtime. Follow the steps below to fix the issue.

Common Causes

Moving from traditional network shares or NAS devices to Microsoft 365 allows your team to collaborate in real time, access files from any device, and eliminate version control headaches. This guide walks you through migrating your office files to SharePoint Online and OneDrive for Business.

Quick Fix Steps

1. Audit your existing server shares and identify which folders are actively used.
2. Create a corresponding site structure in SharePoint Online.
3. Map user permissions from your old server to SharePoint groups.
4. Migrate data using the SharePoint Migration Tool or a third-party migration utility.
5. Point users to OneDrive for Business for personal files and SharePoint for team files.
6. Retire the old server only after verifying all data and permissions have transferred correctly.

Detailed Instructions

1. Audit your current file server

1. Log in to your existing file server or NAS device.
2. Review all shared folders and identify which ones are still in active use.
3. Note any folders with broken permissions, orphaned files, or outdated data that can be archived rather than migrated.
4. Document the current folder hierarchy so you can replicate it in SharePoint Online.

2. Plan your SharePoint site structure

1. Open a web browser and navigate to the SharePoint admin centre.
2. Create a new team site for each department or major project group.
3. Use a consistent naming convention, such as Finance-Documents or Marketing-Assets.
4. Create document libraries within each site to mirror your old folder structure.
5. Avoid creating too many nested folders; SharePoint works best with flat structures and metadata.

3. Map permissions and access groups

1. Review the NTFS permissions on your existing shares.
2. Create Microsoft 365 groups or SharePoint groups that match your existing access levels.
3. Assign Members to staff who need edit access and Visitors to staff who need read-only access.
4. For sensitive folders, use unique permissions rather than inheriting from the parent site.

4. Migrate your data

1. Download and install the SharePoint Migration Tool from Microsoft.
2. Sign in with your Microsoft 365 administrator account.
3. Select your source file share or NAS path.
4. Select the destination SharePoint site or OneDrive for Business location.
5. Run a pilot migration with a small folder first to verify timing and accuracy.
6. Schedule the full migration during a quiet period to minimise impact on users.
7. Monitor the migration log for any failed files or permission errors.

5. Transition users to OneDrive and SharePoint

1. Ask staff to save personal working files to OneDrive for Business instead of their local C:\Users\ profile or desktop.
2. Direct team collaboration files to the relevant SharePoint document library.
3. Show users how to sync SharePoint libraries to File Explorer using the OneDrive sync client.
4. Demonstrate co-authoring: multiple staff can open the same Word or Excel file in Microsoft 365 apps and edit simultaneously.
5. Explain version history: users can click File > Info > Version History to view and restore previous versions.

6. Decommission the old server

1. Keep the old server online in read-only mode for at least two weeks after migration.
2. Verify that all critical files are accessible in SharePoint and OneDrive.
3. Confirm that staff no longer rely on mapped network drives before powering down the old hardware.
4. Archive the old server data according to your organisation's data retention policy.

Troubleshooting

Files fail to migrate

• Check that file names do not contain unsupported characters such as ", *, :, <, >, ?, /, \\, or |.
• Ensure file paths are not too long; SharePoint has a limit of 400 characters for the full file path.
• Verify that the migration account has read access to the source folder.

Users cannot access migrated files

• Confirm the user has been added to the correct SharePoint group or Microsoft 365 group.
• Check that the user has the appropriate licence assigned in the Microsoft 365 admin centre.
• Ask the user to clear their browser cache or sign out and sign back in to Office apps.

Sync conflicts in OneDrive

• If a conflict occurs, OneDrive creates a separate copy. Users should compare versions and save the correct one.
• Ensure the OneDrive sync client is up to date.

Version history is missing

• Version history must be enabled on the SharePoint document library.
• Go to Library Settings > Versioning settings and ensure Create major versions is selected.
• Older files migrated without history may not show previous versions; this is expected for content moved from a legacy file server.

Once your migration is complete, your team will benefit from real-time collaboration, automatic version control, and secure access to files from anywhere. If you host with us, you don't need to do this yourself — just Open a Ticket and our Brisbane team will get it sorted.

Still Having Issues?