UNABLE TO CO-AUTHORIZING IN EXCEL

lyden 0 Reputation points
2026-09-08T06:41:24.83+00:00

Hi, I recently changed my hard disk. Before changing it, my coworker and I were able to access and edit a file that I had previously shared without any issues.

However, after changing the hard disk, I noticed that my coworker can no longer edit the Excel file while I have it open. I can work on the file normally, but my coworker has to wait until I close the workbook before he can continue working on it.

I have tried sharing a new link and have also tried creating a completely new workbook, but the issue still persists. The file is already uploaded to OneDrive, and I have tried all the suggested troubleshooting steps. My Excel is also updated to the latest version.

What I would like is to enable the sharing feature where a guest can edit the Excel file simultaneously without needing to sign in. This feature was working for me before I changed the hard disk. I’m not sure if changing the hard disk is related to the issue. I only mentioned it because the problem started occurring around the same time.
Screenshot 2026-09-08 at 15.24.47.png

Could you please help me identify what might be causing this issue and how I can restore the same functionality?

Microsoft 365 and Office | Excel | For business | Windows
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  1. AI answer

    2026-09-08T06:41:47.1733333+00:00

    The hard disk change is unlikely to be the direct cause. The behavior described matches a co-authoring lock condition, which usually happens when at least one requirement for co-authoring is no longer being met.

    Based on the supported causes, check these items in order:

    1. Confirm both people are using a co-authoring-supported Excel app If just one person opens the workbook in a version of Excel that does not support co-authoring, everyone else gets the locked message. Supported versions include:
      • Excel for Microsoft 365
      • Excel for Microsoft 365 for Mac
      • Excel for the web
      • Excel for Android
      • Excel for iOS
      • Excel Mobile
      Excel 2016, 2019, and 2021 LTSC do not support co-authoring. A good test is to have both people open the workbook in Excel for the web. If co-authoring works there, the issue is with the desktop app/version/sign-in state.
    2. Make sure the workbook is in a supported location Co-authoring is available when the file is stored on:
      • OneDrive
      • OneDrive for Business
      • SharePoint in Microsoft 365
      If the file is being opened from some other server or location, co-authoring may not work.
    3. Check the file format For Excel co-authoring, use one of these formats:
      • .xlsx
      • .xlsm
      • .xlsb
      Co-authoring does not support the Strict Open XML Spreadsheet format. If needed, open the file and save it again through File > Save As > Browse and choose .xlsx, .xlsm, or .xlsb.
    4. Verify the workbook is not using a feature that blocks co-authoring Co-authoring is unavailable if the file is:
      • checked out from SharePoint
      • encrypted with password protection
      • marked as final
      • using IRM/DRM
      • containing ActiveX controls
    5. Check permissions If the other person only has view permission, co-authoring will not be available. In Excel, a user with view-only access can use Viewing > Request more access to ask for edit permission.
    6. Check whether the file is still temporarily locked by a stale session If Excel thinks the file is still open:
      • close the workbook on all devices
      • wait a few minutes for the server to release the lock
      • if needed, close Excel and restart Windows
    7. Check the OneDrive sync app If the file is being opened through the OneDrive sync app, make sure:
      • the sync app is the latest version
      • syncing is not paused

    For the specific requirement of allowing a guest to edit simultaneously without signing in, the provided material does not document anonymous guest co-authoring behavior or settings. The supported guidance here is to verify co-authoring prerequisites: supported app version, supported storage location, supported file format, edit permissions, and absence of blocking features.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

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  2. Hani-Ng 1,130 Reputation points Independent Advisor
    2026-09-08T07:48:28.9766667+00:00

    Please note that our forum is a public platform. Kindly ensure that you hide any personal or organizational information to protect personal data.  

    Hi leyden

    I would first recommend reviewing the AI's recommendations, as they cover the main co-authoring requirements and common issues that can prevent simultaneous editing.

    In addition, since you have already tested with newly created workbooks, new sharing links, and files stored in OneDrive, it may be helpful to determine whether the issue is related to the way the workbook is being accessed rather than the workbook itself.

    To better understand the situation, could you please provide the following information?

    • Is the guest opening the file in Excel Desktop or Excel for the web?
    • Does the issue occur only when using an Anyone with the link can edit sharing link?
    • If you share the file directly with the collaborator's email address and have them sign in with a Microsoft account, does co-authoring work as expected?

    As a test, please try having both users open the workbook in Excel for the web at the same time. If simultaneous editing works there but not in the desktop application, that would suggest the issue is related to the local Excel or OneDrive session on the rebuilt computer rather than the file itself.

    Also, the hard disk replacement itself would not normally affect co-authoring. However, because the issue started immediately after the device change, it may be worth investigating the Office and OneDrive sign-in status on the new installation, particularly if the behavior differs between signed-in users and anonymous guest access.

    Once you have had a chance to run these tests, please let me know the results. I look forward to your response.

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