Moving a file server or shared drive to SharePoint and OneDrive works well for most small businesses — as long as you clean the data up first, design the destination instead of copying the old folder tree, and rebuild permissions around groups. Check four limits before you start: storage of 1 TB plus 10 GB per licence, a 400-character limit on the full path including the file name, a list of characters and names SharePoint won’t accept, and Microsoft’s recommendation to sync no more than 300,000 files to any one computer. Then use Microsoft’s free tools to run a pilot, a main copy and a catch-up pass before cutover.
This checklist covers whether your server should move at all, the limits that cause failures, clean-up, designing sites and libraries, permissions, the migration tools, cutover and what to do afterwards. If your email and accounts are moving at the same time, start with our Microsoft 365 migration checklist.
Should the file server move to SharePoint?
The move usually makes sense when:
- You already pay for Microsoft 365, so the storage is included.
- Staff work from home or more than one office, and the VPN is the bottleneck.
- The server is due for replacement and the main thing it does is hold files.
- You want version history and the ability to restore a single file without calling anyone.
Some content shouldn’t go into a synced document library, or needs a different plan:
- Database files opened by an application. Accounting company files, Access databases and folders a line-of-business system writes to directly. Check the vendor’s guidance; many need a server, a hosted version of the application or the vendor’s own cloud.
- Very large files edited all day. Video, big CAD assemblies and design files can work, but test them over your real internet connection first.
- Outlook PST files. Supported, but Microsoft notes they sync less frequently than other files. Better to import them into mailboxes or archive them.
- OneNote notebooks. They have their own sync mechanism, a 2 GB limit when stored in OneDrive or SharePoint, and should be moved through the OneNote app rather than dragged into a synced folder.
If the server also runs applications, our server vs cloud cost comparison helps decide what replaces it.
The limits that cause migration problems
These figures come from Microsoft’s published SharePoint limits and its OneDrive and SharePoint restrictions page. Check them against your data before you plan anything else.
| Limit | Value | What it means for a migration |
|---|---|---|
| Organization storage | 1 TB + 10 GB per licence | A 20-person business gets about 1.2 TB, not counting each user’s OneDrive. Size the archive first |
| Over the storage limit | Read-only risk | Users may be unable to add or edit content until usage drops or storage is added |
| Recycle bins | Count toward storage | Deleted files still use space until the recycle bin is emptied |
| Largest file | 250 GB | Rarely a problem outside video and disk images |
| Path length | 400 characters, decoded, including the file name | The most common failure. Deep folder trees and long names hit it quickly |
| Characters not allowed | " * : < > ? / \ | | Files using them must be renamed; the tools can flag or replace them |
| Names not allowed | .lock, CON, PRN, AUX, NUL, COM0–9, LPT0–9, desktop.ini, anything starting with ~$, and _vti_ anywhere | Also no leading or trailing spaces in file or folder names |
| Items per library | 30 million | Permissions inheritance can’t be broken on a list, library or folder holding more than 100,000 items |
| Unique permissions per library | 50,000 supported, 5,000 recommended | A reason not to copy folder-by-folder permissions from the old server |
| Sync | 300,000 files recommended maximum | Across everything a computer syncs, including shortcut folders |
| Moving between sites later | 100 GB and 30,000 files per operation | Get the structure right first; large reorganisations afterwards are slower |
Clean up before you move
Every file you migrate costs time, storage and sync performance. A file server that has grown for ten years usually carries a lot of material nobody needs, and the migration is the cheapest moment to leave it behind.
Clean-up tasks, before the first copy
- Size the data: total volume, file count, and the largest folders. Compare it with your SharePoint storage.
- Run a path-length report and shorten or flatten anything near 400 characters, remembering the new site and library names add to the path.
- Find and fix invalid characters, reserved names and leading or trailing spaces.
- Agree a retention rule with each team — for example, projects closed more than seven years ago move to an archive, not the new library.
- Remove duplicates, installers, temporary files and old copies of ‘final_v3_REALLY_final’.
- Identify PST files, OneNote notebooks and application data folders, and plan them separately.
- Find files with no clear owner and assign one before the move, not after.
- Take a full, tested backup of the server before anything changes.
Design the destination: sites, libraries and Teams
The most common mistake is recreating the old drive letter: one enormous library with the same twenty top-level folders. It works, but it carries over every old problem and makes permissions harder.
- One site per team or function. Finance, operations, projects, HR. Each SharePoint team site has its own owners, members and settings, which is where permissions should live.
- Teams where people collaborate. A team in Microsoft Teams creates a SharePoint site behind the scenes, and its Files tab is that site’s library. If a department works in Teams, put its files there.
- Libraries for distinct types of content. Active projects and closed projects, or client files and templates, rather than one library holding everything.
- Shallow folders. Folders still work in SharePoint. Keep them to three or four levels so paths stay short and people can find things.
- A hub to tie it together. A hub site gives the intranet shared navigation and search across related sites without merging them.
Draw the map on one page — sites, libraries, owners and who gets access — and agree it with each team before copying anything. It’s much easier to change a diagram than a library holding 200,000 files.
Permissions: simplify, don’t copy
File servers tend to accumulate permissions set folder by folder over many years. Copying them across reproduces the confusion and can run into Microsoft’s recommended limit of 5,000 unique permissions per library. Rebuild instead.
- Use groups, not individuals. Grant access to a Microsoft 365 group or security group, and manage membership there.
- Set access at the site, not the folder. If a folder needs different access, that’s usually a sign it belongs in its own library or site.
- Decide external sharing up front. Who can share with people outside the company, whether links expire, and whether “anyone with the link” is allowed at all.
- Name owners for every site. Two per site, so access requests don’t stall when one is away.
- Test as a regular user. Sign in as someone in each group and confirm they can see what they should — and nothing they shouldn’t.
Our cybersecurity checklist covers the sign-in and sharing settings that should be in place before your files are reachable from anywhere.
Migration tools
Dragging folders into a browser or a synced library works for a handful of files and fails quietly for anything bigger. Microsoft provides two free tools built for the job.
| Tool | How it runs | Good for |
|---|---|---|
| SharePoint Migration Tool (SPMT) | A desktop application on one computer with access to the share | Smaller moves. Settings cover version history, hidden files, date filters, excluded file extensions and how invalid characters are handled |
| Migration Manager | Run from the SharePoint admin centre, with agents installed on Windows machines; tasks are handed to the next available agent automatically | Larger file shares, or several shares migrated in parallel, with central reporting |
Both tools copy file metadata such as created and modified dates, report every file that failed and why, and support incremental runs that copy only what changed since the last pass. Complex cases — very large volumes, tenant-to-tenant moves or other platforms — may justify a third-party migration tool.
Pilot, incremental passes and cutover
- Pilot with one team. Migrate one department’s files, let them work for a week, and fix what they find: missing files, broken links in spreadsheets, permissions that don’t match how they work.
- Run the main copy. Copy everything else while people keep working on the old server.
- Review the failure report. Every file that didn’t move, with the reason. Fix and re-run.
- Communicate the date. Tell staff when the old drive stops changing, where their files will be, and how to open them — browser, Teams or the OneDrive app.
- Freeze the old share. Make it read-only at the agreed time, usually Friday evening.
- Run the final incremental pass. Only the changes since the main copy, so it’s quick.
- Switch people over. Remove mapped drives, set up sync for the libraries each person needs, and fix the links in templates and shortcuts.
- Be on hand Monday. Most questions arrive in the first two hours.
After the move
The first sixty days
- Keep the old server read-only for an agreed period, typically 30 to 60 days, then archive and retire it.
- Confirm your Microsoft 365 data is backed up independently — version history and the recycle bin aren't a backup plan.
- Set retention policies that match your record-keeping obligations.
- Review sharing links and external access a month in, and again after three months.
- Watch storage, including recycle bins, and set an alert before you approach the limit.
- Give each site owner a short guide: how to add people, restore a file and recover a deleted folder.
Our backup and disaster recovery guide covers protecting Microsoft 365 data, and our Google Workspace vs Microsoft 365 comparison helps if you’re still choosing a platform.
YVR Technology plans and runs file server and SharePoint migrations as part of our cloud services, for businesses across Greater Vancouver and the Fraser Valley including Vancouver, Burnaby and Richmond, and remotely for businesses elsewhere in B.C. If you’d like a migration plan before you commit, get in touch.