Microsoft Azure Files Shares not saving files (transfer failed)

Hannah O'Loughlin 20

Azure is not allowing us to save files (specifically, Microsoft Azure Storage Explorer)

Error message - Transfer of 'xxx' to 'yyy' failed: 0 items transferred (used SAS, overwrite enabled, discovery completed)

Praveen Bandaru 11,310 Reputation points Microsoft External Staff Moderator

2026-03-20T21:18:30.39+00:00
Hello Hannah O'Loughlin

It seems that Storage Explorer can detect your share using the SAS, but no data is actually transferred. This often indicates that the SAS, network rules, or share settings might be preventing write operations. Here’s a brief checklist to help troubleshoot:

Share the below details for further investigation on the issue:

The exact error code or HTTP status from the Storage Explorer log?

How you generated the SAS (Portal, CLI, code) and the permissions you selected?

Whether your storage account has any firewall/VNet rules or private endpoints enabled?

The size/number of files you’re trying to upload (in case you’re hitting any limits)??

Verify your SAS token ensure your SAS token is still valid and provides at least “Create”, “Write”, and “Delete” permissions, or use “All” for testing purposes. If you created the SAS with CLI or PowerShell, consider regenerating it with a longer expiry and full access to eliminate permission issues.

Also, check your file share quota. In the Azure portal, navigate to your storage account, then File shares, and select your share. Review the Used versus Quota values—if the share is full, you won’t be able to add more files.

Check your networking and firewall rules. If your storage account is restricted to specific networks or uses a private endpoint, verify that your client IP or VNet is permitted. For private endpoints, ensure that DNS resolves .file.core.windows.net to the correct private IP. You might also want to try using a different client or protocol.

Try using Azure Storage Explorer on a different machine or test with the Azure Storage REST APIs (such as AzCopy) to determine if the issue is specific to one client. If you’re connecting via SMB (port 445), you can run Test-NetConnection .file.core.windows.net -Port 445 to confirm outbound connectivity. Also, review the Storage Explorer logs for any errors.

Check the below reference documents for more understanding:

https://learn.microsoft.com/en-us/troubleshoot/azure/azure-storage/files/connectivity/files-troubleshoot?tabs=powershell

https://learn.microsoft.com/en-us/azure/storage/files/create-file-share?tabs=azure-portal

https://learn.microsoft.com/en-us/azure/storage/common/storage-sas-overview

I hope the above answer helps you! Please let us know if you have any further questions.

Please don't forget to "upvote" where the information provided will help you, this can be beneficial to other members of the community.
Hannah O'Loughlin 20 Reputation points

2026-03-20T21:43:27.72+00:00

Hi Praveen,

Thank you for the response. We have paid for standard support; can we schedule a call to troubleshoot?

Thanks!
Praveen Bandaru 11,310 Reputation points Microsoft External Staff Moderator

2026-03-21T04:44:56.62+00:00

Hello Hannah O'Loughlin

I have also initiated a private message. Please check it and provide the necessary information so we can discuss further on your concern. Check the below screen shot to find private message option.

Answer accepted by question author

Praveen Bandaru 11,310 Reputation points Microsoft External Staff Moderator

2026-03-25T16:02:41.6633333+00:00

Hello Hannah O'Loughlin

When using the storage explorer to download and upload files, you are encountering some issues during these operations.

Downloading files works successfully, and you are able to access the file.

However, when you try to modify and save the opened file, you experience a problem getting the error.

Note: If you make any changes to the file, please save it before uploading. Be sure to close the file first, then try uploading it. Uploading an open file is not possible.
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2 people found this answer helpful.
Matthew Medeiros 0 Reputation points

2026-03-25T16:24:07.8766667+00:00

Thank you - that seems to work.

Praveen Bandaru 11,310 Reputation points Microsoft External Staff Moderator

2026-03-28T17:04:06.5166667+00:00

Hello Hannah O'Loughlin

I just wanted to follow up and see if you had a chance to review my answer to your question. Please let us know if you found it useful, and don't hesitate to contact us if you have any further questions.

I hope the above answer helps you! Please let us know if you have any further questions.

Please don't forget to "accept the answer" and "upvote" where the information provided will help you, this can be beneficial to other members of the community.
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1 additional answer

Q&A Assist

2026-03-20T20:49:13.9466667+00:00

AI generated content. This question contains an answer created with AI from Q&A Assist. Learn more
The error indicates that Storage Explorer attempted the upload (discovery completed) but the transfer was blocked before any items were written. Based on similar Azure Files issues, the most common causes are:
1. Network/firewall restrictions on the storage account
  
  If the storage account has firewalls or virtual network rules enabled, the client IP (or proxy IP, if behind a proxy) must be allowed.
  
  Action:
  
  In the Azure portal, open the storage account → Networking.
  
  If “Selected networks” is configured, ensure the public IP actually used by Storage Explorer (often the proxy’s IP) is in the allowed list.
  
  As a test, temporarily set “Allow access from all networks” and retry the upload. If it works, re‑enable restrictions and correctly add the required IPs or VNets.
2. Authorization/permissions mismatch when using SAS or Entra ID
  
  For SAS:
  
  Ensure the SAS has write (w) and create (c) permissions for file shares and is not expired.
  
  If the SAS was generated before firewall changes or key rotation, regenerate it and reconnect Storage Explorer.
  
  For Entra ID/OAuth:
  
  Azure Files via REST/Storage Explorer requires the correct data‑plane role. If using Entra ID, assign Storage File Data Privileged Contributor at the storage account or file share scope to the identity used in Storage Explorer, then retry.
3. File locks, leases, or open handles blocking overwrite
  
  If overwrite is enabled but the target file is locked or has an open handle/lease, the write can fail.
  
  Action (from a PowerShell session with Az module ≥ 2.4):
  
  Use Get-AzStorageFileHandle to list open handles on the affected path.
  
  If all clients have closed files but handles remain, use Close-AzStorageFileHandle to force close them, then retry the upload.
4. Backup/resource locks or share leases
  
  Azure Backup or admins may have placed resource locks or share leases that prevent modification/deletion.
  
  Action:
  
  In the storage account, check Locks for ReadOnly or Delete locks that might affect the file share.
  
  If Azure Backup is configured for this share, verify there is no active restore or lease blocking changes; adjust or break the lease if appropriate.
5. Parallel operations or backup/restore conflicts
  
  If Azure Backup is restoring to the same share, or another data‑movement job is running, writes may fail.
  
  Action:
  
  In the Recovery Services vault, confirm there is no ongoing restore to the same file share.
  
  Wait for any backup/restore job to complete or target a different share.
If, after checking the above, uploads still show “0 items transferred,” capture the detailed error from Storage Explorer’s Activity Log (including HTTP status and x-ms-error-code) and correlate it with:
- Storage account Metrics/Logs for failed requests.
- Any recent changes to networking, keys/SAS, or RBAC.
References:
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