SharePoint File Handler preview not being called. Used to work. Same File Handler preview works for OneDrive.

Question

We have had a File Handler defined for our product for years. The same File Handler definition is in place for our OneDrive and SharePoint integration (single OAuth2 app registration). Up until several months ago, the "Preview" was called correctly on both OneDrive and SharePoint (see attached). However, now customers see a page with “Hmm …. looks like we’re unable to preview this file”. This same File Handler Preview is still working correctly under OneDrive.

All other parts of our File Handler still work in SharePoint ("new", "open" and display of our file icons). This same preview works correctly in OneDrive. In SharePoint, the user sees a page reading "Hmm... looks like we are unable to preview this file" (see attached). It offers an "Open" button just below that; if the user clicks that, it does not go to the File Handler open, it appears to try to open the file as a folder (which is definitely broken behavior).

That page does recognize our File Handler. The "Open" control in the top right has a link to our File Handler's "open".

This used to work correctly (have a screen shot that demonstrates it).

We need Microsoft to fix SharePoint to correctly use the File Handler preview.

image-20241004-214950.png

Answer 1

Hi @Steve Niles ,

Thank you for posting in this community.

It seems that you are experiencing issues with the File Handler preview in SharePoint, while it continues to work correctly in OneDrive. Since we don't have access to test it, we can't rule out the exact cause of the problem.

To address this issue, you might consider the following steps:

Check for Updates: Ensure that your File Handler definition and OAuth2 app registration are up-to-date with the latest Microsoft updates and guidelines.

Contact Support: Reach out to Microsoft support with detailed information about the issue, including screenshots and any error messages. They might be able to provide a fix or workaround for the problem.

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