That's strange! Are you sure you got the new "release" version of Firefox 38.0 and not a "beta" version issued over the past few weeks? The release version is available here:

https://www.mozilla.org/firefox/all/ (scroll down to your preferred language)

By the way, although Firefox 38.0 was released yesterday, there is a system to trickle out the update so that in case there is a huge problem with it, not all users are affected immediately. So checking for updates using the About Firefox dialog will not always find the update during the first few days after its release.

I had downloaded the final release of the v.38 update. I've downloaded both the British English and US English versions and received the same message when trying to drag the DMG to my Application folder. Please see screen grab attached.

Hmm, I can't explain it. I don't know what MacOS is comparing.

You may want to wait a couple days, a quick update to Firefox 38.0.1 is due out later this week.

Hello, after downloading don't forget to trash the current Firefox application and then install the version that you have downloaded.

thank you

Whoa! If I do that I'll loose all my bookmarks and extensions. And I can't find a way to export bookmarks for later import. This doesn't seem like a solution.

Okay. I think your suggestions is better than Ideato's, which was to trash my current version (saying goodbye to all my bookmarks, add-ons, and extensions) before installing v.38.

I'm pretty sure there is a way to trash an application without removing all its associated data. But someone will need to get me a Mac to confirm it for myself. ;-)

Inspiredmac said

Whoa! If I do that I'll loose all my bookmarks and extensions. And I can't find a way to export bookmarks for later import. This doesn't seem like a solution.

No, you don't lose anything if you do not select to remove your personal data, your profile data is stored elsewhere in the Firefox Profile Folder, so you won't lose your bookmarks or other personal data.

see also: How to download and install Firefox on Mac

thank you

But wait....... Firefox 38 was pulled from release due to a stability issue. It will be released in a day or two as Firefox 38.0.1.

thanks again

New v. 38.0.1 has blocked access to preferences with an inactive questions page. I downloaded v.37.0.2 offered by Mozilla as an alternative but problem v. 38.0.1 pops back up on each turn-on.

Hi delbablo, your question seems to be about a different issue, but I'll give you a quick reply. If this doesn't help, I suggest starting a new question (at the top of the page Ask a Question link).

Firefox 38 switched from using a pop-up dialog for Preferences to using a page-based dialog. As another way to load that page, you can try typing or pasting about:preferences in the address bar and pressing Enter/Return to load it.

If you find that you can't load or can't get used to the "in-tab" preferences dialog, there is a preference to return to the old style dialog:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.

(2) In the search box above the list, type or paste pref and pause while the list is filtered

(3) Double-click the browser.preferences.inContent preference to switch it from true to false

Note: I don't know whether that will be in Firefox forever or is a transitional feature.

Tried your suggestion but the same window persists. It asks for all set up data for all 8 panels in preferences with no way to enter the data. Problem began with Firefox 38.0.1 update and seems to be a locked in block. I will keep loading 37.0.2 for preferences access until a corrected version is available.