Hi, please open WIn10 Settings --> Apps --> Default Apps and Check if PDF is in the list and what is set to open it. If it is Firefox change to DC.

Under heading Apps and Features go through the page and click on stuff and see if can find PDF or DC. I do not have Adobe installed as of yet, as had a motherboard meltdown.

See if can find something in Windows to make DC the Default.

I did both of these things and am still having this issue. Firefox keeps defaulting back to "Save File". Let me know if you need me to send you a screenshot. This is super annoying. thanks

Are you sure it's a properly formatted pdf file or pdf file link?

Nope, no weird Adobe links or documents. The setting just randomly changes and I always have to go back in and change it. Very frustrating.

Hi, yup is. Is It changing in Firefox or is it changing in Windows ? or Both ?

Fix Windows 10 registry and System Files, note it goes online for new ones.

• Please use the Windows key + X keyboard shortcut to open the Power User menu and select Command Prompt (Admin).

• Copy/Paste the following command and press Enter:

• DISM /Online /Cleanup-Image /RestoreHealth

It is happening in Firefox. How do I tell if it is happening in Windows?

Also, when I hit the Windows Key + X keyboard shortcut, I don't see Command Prompt (Admin) as an option. Please advise

When does the setting change back from Open in Acrobat to Save File -- for example:

• after exiting Firefox and starting it up again
• after saving a PDF (Firefox remembers that action as the new default)
• randomly
• the change actually never takes at all

Sometimes the settings file that stores download handling preferences becomes corrupted. You can rename the file and have Firefox rebuild it. Here's how:

Open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" Help > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the first table on the page, on the Profile Folder row, click the "Open Folder" button. This should launch a new window listing various files and folders in Windows Explorer.

{MAC} In the first table on the page, on the Profile Folder row, click the "Show in Finder" button. If Finder highlights an icon with a semi-random name like a1b2c3d4.default, double-click it to display the contents of that profile folder.

Leaving that window open, switch back to Firefox and Exit, either:

• "3-bar" menu button > Exit/Quit
• (menu bar) File > Exit (or Firefox > Quit)

Pause while Firefox finishes its cleanup, then rename handlers.json to something like handlersOLD.json. If you see a file named mimeTypes.rdf, rename that one to mimeTypesOLD.rdf.

Start Firefox back up again.

By default, "Portable Document Format (PDF)" will be associated with "Preview in Firefox" so you'll need to update that before testing.

Any improvement?