New Excel workbooks (created in SharePoint library) not launching in app - .xlsx "extension is not valid"

Question

Hi there,

 

Having a recent issue in some SharePoint sites - in Document Libraries, using the (default) New > Excel Workbook action gives the error when launching the app: "Excel cannot open the file 'Book.xlsx' because the file format or file extension is not valid".

• There is some inherited managed metadata in the library but I can't see any issue here and thats been in place for a while. 
• Site/Library Permissions have been checked and no issues found.
• Excel files that were already in the library don't experience this issue (Excel opens successfully).
• It doesn't happen if we upload a .xlsx file to the document library. (Excel opens successfully).
• Excel Files launch fine in the browser. Having tested changing the default to "open in browser" this did temporarily resolve the issue and files created under this setting were then able to launch in the app. However this is not most users' preferred setting.

Can anyone advise what the root cause might be and how we can get newly generated .xlsx workbooks launching in Excel as normal?

 

Thanks,

Alan

Answer 1

Hi @Alan Walker ,

Thank you for posting in this community.

It seems this is not a common issue per my test. However, we can work together to narrow down and resolve the situation. So, Please kindly provide more information below to let us work further.

1.You could try to clear browser cache then restart it.

2.Try to use a different browser or your browser's InPrivate mode to see if the same error occurs.

3.Are other users with permissions facing the same problem? View through another computer or account.

4.Whether all SharePoint libraries have the same problem? You could create a new SharePoint library to check.

5.Check if the same issue occurs with other SharePoint site collections.

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Answer 2

I am having the same issue as described above. The spreadsheet is able to open in the browser but I get the error message when opening it in the desktop app. The issue seems to be the default name "Book.xlsx as I am able to open the file on the desktop app if I rename the file while it is open on the browser.

Microsoft needs more knowledgeable techs to support SharePoint. Thus far every issue I have encountered in SharePoint cannot be resolved because techs are unable to replicate them. This software is becoming useless due to the lack of technical support.