Hi Anibal,
Sorry for the inconvenience it may have caused.
Recent improvements in SharePoint Online have removed the limitations on types of files that can be added. There are currently no known types of files that cannot be added.
The following types of files can be uploaded to SharePoint in a web browser or using the sync app, but they won't work unless the site allows you to run custom script. By default, custom script is blocked on user-created sites that have Microsoft 365 groups.
If you're a global admin or SharePoint admin in your organization, see Allow or prevent custom script to learn how to change the custom script settings.
If your admin allows custom script on a site, you need "Add and Customize Pages" permission (part of the Design and Full Control permission levels) to run the script in the file types listed above. For more info about permissions, see
Understanding permission levels in SharePoint.
For the list of file names restricted by the sync app, see Restrictions and limitations when you sync files and folders.
If this is not your case, to further check the scenario, we would like to collect some information:
- What is the specific format of the Excel file?
- Does the issue occur on all Excel files? Or just this certain one?
- To troubleshoot that the problem is related to a specific document library, please try to do a test in other libraries.
- Please take a screenshot of the error message about “the specified file format is not valid in SharePoint” and share it with us.
For Dynamics 365, as our forum focus on how to deal with the out-of-box issue of Office 365, we are really sorry for couldn't provide a better suggestion for you. We sincerely recommend you raise this in
Microsoft Dynamics 365 Community Forum, which is the official forum for Microsoft Dynamics 365. Experts there would conduct in-depth research on the problem you met and can provide you with more
professional help.
Appreciate your understanding.
Best regards,
Madoc