Firefox stores such actions in handlers.json in the Firefox profile folder.

• https://support.mozilla.org/en-US/kb/change-firefox-behavior-when-open-file

Yes I follow that setup and protocol, but the option reverts back to "down" load for no reason. This as stated happens even when there is no changes or updates to the browser, its just resets to its default.

jim155 said

When i go to options and change the way i handle pdf's eg i want to use Foxit to open and not down load to temp files this will revert back to "down loading" to temp files at some point with out me doing anything or changing my preferences - its annoying, any help welcome.

Hi jim155, are you saying the setting changes to "Save File" on the Options page?

I ask because when an external application is used Firefox saves the file to the Windows Temp folder and then triggers the application to open the file from there (assuming all is working correctly). So having the file saved in the Temp folder is a little ambiguous about what the problem is.

Sorry will try to recap

• Mozilla sets generally by default PDF to "save to"
• In option I change this to "use Foxit Phantom" hopefully you can see the screen snip i uploaded ?

When this is done Mozilla works as should and opens pdf's using the set application, this works for a period of time and then all of a sudden it just will revert back to "save to"

There has been no updates to my knowledge as I control them.

Sounds that there are problems with handlers.json or that Firefox otherwise creates a fresh handlers.json file.

Are you using external cleanup software that might be causing this ?

(In your screenshot) You may have noticed four lines for PDF files. The main one -- Portable Document Format (PDF) -- actually should default to Preview in Firefox, but if the built-in PDF Viewer is disabled, then the setting may default to Save File.

The other three lines reflect non-standard Content-Type headers that various servers have sent to Firefox that got saved with their own instructions. Have you already tried setting those to open in Foxit as well?

If the problem occurs with servers that send non-standard Content-Type headers, I created an add-on to work around that. When it's listening (click its Zzzz button to turn it on), if a file has a .pdf extension, the add-on will correct any weird Content-Type to the correct one (application/pdf).

https://addons.mozilla.org/firefox/addon/content-type-fixer/