hi will. this is the result of security improvements going into the recent firefox version. the best way to fix this problem would be to turn on UAC again on your system - more information about this is available at Drag and Drop errors with Firefox Launcher Process enabled and Windows UAC disabled - How to Fix

Thank you for the reply Philip. According to that article, the drag-and-drop restrictions only apply with "Launcher Process Enabled." But what exactly is the Launcher Process? I can't find any information on this with an internet search.

It would be disappointing if the only two fix options are either to deal with UAC or to disable Firefox's security improvements. But could I just disable the Launcher Process?

Hi WillW, there is a preference to disable the Launcher Process feature, but we're all new to it so we don't know the implications. If you want to try it:

(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 or accepting the risk.

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

(3) Double-click the browser.launcherProcess.enabled preference to switch the value from true to false

Thank you for that information jscher. I don't think I'll try disabling it without knowing what the consequences would be, but I'm glad to at least know how.

I do hope Mozilla is planning on providing documentation about this before too long.

with turning off the launcher process altogether you're worse off security wise than using the workaround described in the article - that's not a recommended way to proceed...

edit: some more information about what the launcher process is doing is available in this mailing list entry: https://groups.google.com/d/msg/mozilla.dev.platform/xSyK4r54Ifs/ncc-8irMDAAJ

What happens if you use Save in the Download dialog and then launch the ZIP from the Downloads arrow list on the main toolbar? Is 7-Zip still run with reduced privileges or does it run normally in that case?

jscher2000 said

What happens if you use Save in the Download dialog and then launch the ZIP from the Downloads arrow list on the main toolbar? Is 7-Zip still run with reduced privileges or does it run normally in that case?

The answer is that 7-Zip (or Windows Explorer, if I set it as the default .zip handler) still runs with reduced privileges, just as if Firefox had opened it automatically. So, drag-and-drop doesn't work with that method either.

I'm really puzzled about how this works, but I'm running Windows 10 with the default UAC setting (which isn't very obtrusive any more; far different from Windows XP SP2) so I can't test out what you're experiencing.

It makes sense to me what Mozilla did, from a security perspective. Adds a bit of hassle for a minority of users like me, but the trade-off is probably worth it.

Mozilla has apparently disabled the -no-deelevate workaround that allowed us to save files to Windows Explorer. So now once again there is no way for me to download or save files from the internet anymore when using Firefox.

I am so extremely frustrated right now.

WillW said

Mozilla has apparently disabled the -no-deelevate workaround that allowed us to save files to Windows Explorer. So now once again there is no way for me to download or save files from the internet anymore when using Firefox.

You shouldn't need to use -no-deelevate to save files. That was needed if you disabled UAC and Firefox was unable to drag-and-drop to Windows Explorer because it was running at a lower privilege level. As far as I know, it should still work for that.

Could you describe what's happening in more detail?

jscher2000 said

WillW said

Mozilla has apparently disabled the -no-deelevate workaround that allowed us to save files to Windows Explorer. So now once again there is no way for me to download or save files from the internet anymore when using Firefox.

You shouldn't need to use -no-deelevate to save files. That was needed if you disabled UAC and Firefox was unable to drag-and-drop to Windows Explorer because it was running at a lower privilege level. As far as I know, it should still work for that.

Could you describe what's happening in more detail?

In Firefox 69.0 / 69.0.1, when I right-click an image and select "save image as..." and then try to save it to my hard drive, it always fails. There is no error message from Firefox, just that the file does not download to my hard drive.

I actually attempted to disable the Firefox launcher process, from an answer you gave earlier in this thread, in an attempt to fix the problem. But even that didn't work.

I was able to use another workaround from a different help page, which involved copying the image and then pasting it into a Windows folder. However that would be too much of a hassle to remember every time I want to save an image to my hard drive, especially since Firefox isn't giving any error message when the pictures don't save (I only just found out that all of the images I've tried to save over the last 2 weeks have failed).

The only solution that works for me at this time is to revert back to Firefox 68.0.2, which is what I'm using now.

Please ignore the content in my most recent two replies that regards downloading images. That problem is caused by an extension, not Firefox.

However, there is still the problem that the -no-deelevate launch property no longer works in Firefox 69. And the associated help document has not been updated with an alternative:

https://support.mozilla.org/en-US/kb/windows-administrator-launcher-process-error-fix

Hi WillW, yours is the first report I've seen that -no-deelevate stopped working in Firefox 69. I am not aware of that having been removed from Firefox, so I think we'll have to wait for more reports and see whether there is a pattern to it.