OneDrive not syncing after migration is almost always a sign-in problem on the PC, not a data problem in the cloud. The sync app still holds the old tenant account, cached identity or old folder link. Unlink the old account, clear the cached sign-in data, sign in with the new account and check the status.
Why is OneDrive not syncing after migration?
Because the files moved and the PC did not. The sync app on every laptop was signed in to the old tenant, and it remembers that account.
A tenant migration copies data between two cloud accounts. It does not reach into every user's computer and change who the sync app is signed in as. So the person opens the laptop on Monday and OneDrive not syncing after migration is the first thing they see, because it still points at the old account, the old folder and the old sign-in page. Nothing in the cloud is broken. The device simply has not been told about the new account.
Microsoft's own troubleshooting page describes the same case. After a tenant to tenant migration, a UPN change or a password update, OneDrive for Business may be unable to sync, and the fix starts with clearing the stored sign-in data. If you have not moved the files yet, start with how to migrate OneDrive from one tenant to another.
Users do not report a migration as late or early. They report it as the Monday their files stopped showing up. The sync step is the part of the project they will actually feel.
Jamie Kaler Marketing Head and Content Strategist, RecoveryTools
Which sync errors appear after a OneDrive migration?
Five show up again and again. Match what the user sees to this table before you touch anything.
| What the user sees | Likely cause | Fix |
|---|---|---|
| Sign in box keeps naming the old tenant | Cached identity from the old account | Clear the IdentityCache and OneAuth folders |
| AADSTS50020 account does not exist in tenant | Signing in with an account that is not in that tenant | Sign out, use the new account and clear cached identities |
| OneDrive shows the old account and folder | Old account still linked to the PC | Unlink this PC, then sign in with the new account |
| Files stuck on pending or red cross | One file blocks the queue | Pause sync, move the file out, resume and move it back |
| Desktop and Documents still sit in the old folder | Folder backup was set up on the old account | Move the files, then set up folder backup on the new account |
Most of these clear with the same steps, so the order matters more than the diagnosis. The full order is further down this page.
What does AADSTS50020 mean after a tenant move?
It means the account you signed in with is not a member of the tenant you are trying to reach. Microsoft's own answer is that the account must exist in that tenant, as an external user if need be, before it can sign in.
After a migration there are two common reasons. The user typed the old address into a new tenant's sign in page, so the account really does not exist there. Or cached identities from the previous tenant are still in use, which Microsoft calls out as the usual cause during tenant to tenant migrations.
The fix has three parts. Sign out. Remove the cached Microsoft Office identities. Sign in again with the new account. If the error survives all three, ask the tenant admin to confirm the account exists and is licensed. Do not add the old address as a guest to make the message go away, because that connects the user to the wrong tenant on purpose.
How do you fix OneDrive not syncing after migration?
Do these in order on one affected PC. They follow Microsoft's published guidance, and the first four fix most cases.
- Check the new account in a browser. Sign in to Microsoft 365 with the new address and open OneDrive online. If the files are not there, the problem is the migration, not the PC.
- Unlink the old account. Open OneDrive settings, go to the Account tab, select Unlink this PC and confirm.
- Close OneDrive and Office apps. Make sure nothing is still holding the old identity open.
- Clear the cached identity. Delete the OneAuth and IdentityCache folders under %localappdata%\Microsoft. Microsoft names both for this exact case.
- Remove old saved sign-in data. Delete the old tenant entries from Credential Manager and the PreSignInSettingsConfig.json file in the OneDrive settings folder.
- Sign in with the new account. Open OneDrive, enter the new address and choose the folder location. Reuse the old folder only if the files inside it are already in the new OneDrive.
- Check the status. Wait for Up to date, then open a few files and confirm they show the right icons.
- Reset OneDrive if it is still stuck. A reset disconnects every sync connection and starts a full sync afterwards. Microsoft says files are not lost.
Sharing links are a separate topic. People who saved a link to a file will find it points at the old tenant, as explained in what happens to SharePoint sharing links after migration.
How do you reconnect many users at once?
Send one short message with the same steps for OneDrive not syncing after migration, and send it in waves.
Tell users to sign in with the new account, sign in to the sync app with the new account and location, and report anything missing. Microsoft's own post migration steps for its native move say the same three things, and add that old shared links keep working through a redirect. A copy migration works differently, because the new OneDrive is a separate account, so tell users plainly which links will not follow them.
Group users by department so the help desk sees a steady queue, not a spike. Give every group one cutover morning and one named contact. If you moved with Microsoft's native route, remember the admin side as well. Remove the trust relationship on both tenants before the source licenses expire, and remove the redirect sites after the migration is complete.
For a timeline that fits all this into the cutover week, see the Microsoft 365 migration planning checklist.
Keep the new OneDrive current until users reconnect
RecoveryTools OneDrive Migrator copies OneDrive accounts between tenants with versions and original dates. Delta passes move only what changed, so the sync app connects to the final copy once. Sync app settings stay on the PC, so users sign in again and choose their folders.
No credit card, no sign-up. Works on Windows 11, 10 and Windows Server 2022.
What should you protect before users reconnect?
The old local folder, until the new OneDrive is confirmed. It may hold the only copy of a file edited after the last pass.
Before anyone fixes OneDrive not syncing after migration by unlinking or resetting, ask them to save and close their work and note any file they changed in the last day. Do not delete the old sync folder. Rename it, sign in with the new account into a fresh folder and compare the two before you remove anything. Add a last delta pass on cutover day so the cloud copy already has the latest edits.
If you want an independent copy during this window, the Office 365 Backup Tool keeps one outside both tenants. Teams without spare hands for the help desk wave hand it to our cloud migration service.
Frequently asked questions
Why is OneDrive not syncing after a tenant migration?
The sync app on the PC is still linked to the old tenant account. The files moved in the cloud, but the device keeps the old identity, folder link and sign-in data. Unlink the old account, clear the cached identity and sign in with the new account.
How do you fix OneDrive stuck on the old tenant sign in?
Delete the IdentityCache folder under %localappdata%\Microsoft, and the OneAuth folder if needed, then sign in again. Users in a Microsoft community thread reported this fixed a sign in box that kept naming the old tenant.
What causes AADSTS50020 after a migration?
The account used to sign in is not a member of that tenant, or cached identities from the previous tenant are still in use. Sign out, remove the cached identities and use the new account. Ask the admin to confirm the account exists if it persists.
Will resetting OneDrive delete my files?
No. Microsoft says a reset disconnects every sync connection and triggers a full sync afterwards, and files are not lost. Still, save your work first and keep the old local folder until you have compared it with the new OneDrive.
Do old OneDrive links still work after migration?
It depends on the method. Microsoft's native move leaves a redirect so old shared links reach the new location. A copy migration creates a separate account, so links that name the old tenant do not follow the files and need to be shared again.
Does RecoveryTools OneDrive Migrator fix the sync app?
No. It copies the files, versions and dates between tenants. Sync app settings belong to the PC, so users sign in again with the new account and choose their folders. Delta passes keep the new OneDrive current until they do.
Where to start this week
Write one page of reconnect steps and test it on a single real laptop before cutover.
Use a machine with the old account, Desktop folder backup and a few open Office files. If the page works there, it will work for most users. If it does not, you found the gap before the entire company did, and OneDrive not syncing after migration becomes a ten minute fix instead of a help desk spike.
Jamie blends strategic marketing insight with technical writing, turning migration and recovery topics into guidance that works for technical and general readers alike.
Published 12 October 2026. Sync fixes come from Microsoft Learn and Support pages on OneDrive sync problems after migration, fixing OneDrive sync problems and cross-tenant OneDrive migration post migration steps. The AADSTS50020 explanation comes from a Microsoft Q&A answer on AADSTS50020.