This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

mac 10.7.3, ff wouldn't open pdf files on google search, tried web soln. get ff running can't run 2nd ff error, reboot, reloaded (12?) ff, HELP

  • 3 cavab
  • 7 have this problem
  • 4 views
  • Last reply by cor-el

more options

mac 10.7.3, intel dual proc, ff was running great but not opening pdf files from web pages (just opened new page and blank), found ff forum solutions to delete a file, found such file and deleted it, now ff shows error "ff running, can't run 2 ff at same time", rebooted several times, redownloaded ff several times, can't find any ff or mozilla files of any kind in activity monitor or HD, or any library, or in personal library etc,

i think i have ff 12 now loaded, HELP, love ff, how to get it run again thanks

mac 10.7.3, intel dual proc, ff was running great but not opening pdf files from web pages (just opened new page and blank), found ff forum solutions to delete a file, found such file and deleted it, now ff shows error "ff running, can't run 2 ff at same time", rebooted several times, redownloaded ff several times, can't find any ff or mozilla files of any kind in activity monitor or HD, or any library, or in personal library etc, i think i have ff 12 now loaded, HELP, love ff, how to get it run again thanks

All Replies (3)

more options

Can you undelete the file you deleted?? Any idea what it was?


Once you have your Firefox running again, try this recommendation from another thread:

If using a Mac, go to the Firefox Plugins and disable the Adobe Acrobat NPAPI Plug-in, Version 10.1.3. This is a recent plugin update, and as soon as it was installed I noticed that PDFs wouldn't download.

Location: [Menu] Tools/Add-Ons/Plugins

https://support.mozilla.org/en-US/questions/775819

Modified by jscher2000 - Support Volunteer

more options

the deleted file is long gone, ( i can't find the exact thread, but within this same issue ,and it said to open ff, go to a file and then close ff and then delete the file, and then trouble started)

also deleted are multiple down loaded copies of ff, searching for ff, or mozilla, or parentlock and all the other hints from the support mozilla threads on this issue, and i can find nothing (no amount of searching turns up any thing that i can find related to ff-- all other programs are working fine as is safari)

ff is basically dead, i can't get rid of it sufficiently to down load a clean copy, can't find any files to delete,

obviously there is something hiding somewhere, i assume that all my history etc is gone along with any profile info as i can't find any files

if you have any idea of what file name i can search for with finder that might be related to firefox so that i can start over clean, it would be appreciated

and yes i have adobe acrobat and it is the designated pdf file opener, and other pdf files open, the problem was in ff and a web page had a file (like a spec sheet) that was pdf and you click on that and you get a new ff page and blank..

if i remember rightly, this problem is pretty recent, in the last few wks, everything seemed to work before this, i am not a fancy user, just the basic mac programs, ms office, safari, ff, and that's about it

i will disable adobe as you suggest, just as soon as i can get ff up and running again

thanks retired again

more options

Which file(s) did you delete?


Create a new profile as a test to check if your current profile is causing the problems.

See "Basic Troubleshooting: Make a new profile":

If the new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.

See:


You can disable the Adobe Reader plugin in Firefox and use the Adobe Reader program or Preview instead.

  • Firefox > Preferences > Applications > Adobe PDF document : Use Adobe Reader

See [/questions/925119]