Hello. Version 98 changed Settings under Applications on the General page. You may need to change them back to the way you want. Some users have found that certain file types have disappeared from the list. The link below shows how to add them. Users who read and post here have no more influence on how the software is changed than you do.

https://support.mozilla.org/en-US/kb/change-firefox-behavior-when-open-file#w_changing-download-actions

Hello Terry21,

The question is what was the reason to change "Applications" list, and why especially removing "PDF". This has caused a dozen of tickets in the first hours after deplyoment. Removing "PDFs" from the list will affect 100% of the users. The users have all other file types they did set up in the past in the applications list, except PDFs.

Deleting or renaming the handlers.json will not help, since the "PDF" file type will not be put in the list anymore by version 98.

I hope Mozilla does not expect from all of us to go to handlers.json and put in the entry for PDF file types manually, for each user and each profile...

Please could the Firefox developers check this behavior in v98 and make sure that this bug is fixed with the next release?

Otherwise, if this is the way Mozilla goes, it will be very difficult for us IT people to ensure browser support for Firefox in the future.

You can file a bug report at https://bugzilla.mozilla.org/

I notice you have a message about your browser being managed by your organization. Could you open the About Policies page and see whether the PDF Viewer is disabled. Here' how:

Type or paste about:policies in the address bar and press Enter to load that page.

Normally, the "Active" list says: "The Enterprise Policies service is inactive."

However, I suspect you will find something, and possibly it will be the DisableBuiltinPDFViewer policy. If so, that would be a useful data point and might explain why the PDF item isn't pre-populated. Possibly something overlooked in the conversion.

By the way, here is the generic method for an end user to add a new content type to the list:

Open the Downloads list (from the toolbar button or, if needed, Ctrl+J), right-click the file, and choose Always Open Similar Files.

Firefox then should add that file type to the Applications list with a "Use [default application]" action.

If the user prefers to get the Download dialog, they can change it to "Always Ask" using the usual steps: Manage file types and download actions in Firefox.

If the Always Open Similar Files menu item is missing for a download, it usually indicates that the site set Content-Type to "application/octet-stream" instead of "application/pdf" or other specific content-type. This is harder to work around.

Dear jscher2000

Thank you for the advice. Yes, we have the builtin pdf viewer disabled, but this worked until v97. There seem to be other users that haveat least also disabled the builtin viewer and having the same problem.

We've create a KB yesterday for end users as it is described in the Firefox KB. Mozilla should put the pdf file type handling in the applications list again, if empty. It seems something went wrong in the last version, maybe they did not recognize the setting about disabled builtin pdf viewer.

It seems something went wrong in the last version, maybe they did not recognize the setting about disabled builtin pdf viewer.

That is what I think probably happened. You could file a bug: https://bugzilla.mozilla.org/

Do you have a Handlers key in your Policy file?

https://github.com/mozilla/policy-templates#windows-gpo-51

You could try this to set an "Always ask" policy, but would this prevent selecting a different action as the user's preferred default?

Software\Policies\Mozilla\Firefox\Handlers (REG_MULTI_SZ) =

{
  "mimeTypes": {
    "application/pdf": {
      "action": "useSystemDefault",
      "ask": true
    }
  }
}