Firefox 35.0.1 will not start on Yosemite 10.10.2 even with clean install.

Question

I've tried Safe Mode and I've looked for the crash report in Application Support, unfortunately, there is no Firefox folder! Version 33.1 works OK.
The Troubleshooting information below is for version 33, since I can't get 35 to start. I don't know if you'll find anything useful in there or not.
This is from Console:
2/6/15 15:13:59.890 com.apple.xpc.launchd[1]: (com.apple.xpc.launchd.oneshot.0x10000042.firefox[36761]) Service exited with abnormal code: 255
2/6/15 15:14:19.663 com.apple.xpc.launchd[1]: (org.mozilla.firefox.182928[36769]) Service exited with abnormal code: 255
2/6/15 14:33:45.000 kernel[0]: firefox (map: 0xffffff8027d101e0) triggered DYLD shared region unnest for map: 0xffffff8027d101e0, region 0x7fff8da00000->0x7fff8dc00000. While not abnormal for debuggers, this increases system memory footprint until the target exits.
2/6/15 14:33:45.950 firefox[36186]: WARNING: The Gestalt selector gestaltSystemVersion is returning 10.9.2 instead of 10.10.2. Use NSProcessInfo's operatingSystemVersion property to get correct system version number.
Call location:
2/6/15 14:33:45.953 firefox[36186]: 0 CarbonCore 0x00007fff8e20ed9b ___Gestalt_SystemVersion_block_invoke + 113
2/6/15 14:33:45.953 firefox[36186]: 1 libdispatch.dylib 0x00007fff87a22c13 _dispatch_client_callout + 8
2/6/15 14:33:45.953 firefox[36186]: 2 libdispatch.dylib 0x00007fff87a22b26 dispatch_once_f + 117
2/6/15 14:33:45.953 firefox[36186]: 3 CarbonCore 0x00007fff8e1b73ca _Gestalt_SystemVersion + 987
2/6/15 14:33:45.954 firefox[36186]: 4 CarbonCore 0x00007fff8e1b6fb7 Gestalt + 144
2/6/15 14:33:45.954 firefox[36186]: 5 XUL 0x0000000102a5f551 XRE_FreeAppData + 33185
2/6/15 14:33:48.974 2BUA8C4S2C.com.agilebits.onepassword4-helper[529]: 510035 [EXT:0x7f9f4804f700:<OP4ExtensionHTTPConnection: 0x7f9f48047c40>] M webSocketForURI: | [ES4] Extension connected Firefox-Extension 'resource://onepassword4-at-agilebits-dot-com / (null)'
2/6/15 14:36:01.951 Intego Uninstaller[36225]: Activity on Intego folders ((
"/Applications/Browsers Etc./Firefox/Firefox.app/Contents/MacOS/updates/0/"
))- delaying uninstall detection.
2/6/15 14:36:02.075 Intego Uninstaller[36225]: Activity on Intego folders ((
"/Applications/Browsers Etc./Firefox/Firefox.app/Contents/MacOS/updates/0/"
))- delaying uninstall detection.
I hope this is useful. I note that the log entry above suggests I'm running 10.9.2 and the troubleshooting data shows, correctly, that it is 10.10.
Sincerely,
Craig

Answer 1

There may not be a profile since the Firefox folder is empty.
Can you try to run the profile manager to start Firefox and see what the error is there:
In a terminal run this:
/Applications/Firefox.app/Contents/MacOS/firefox-bin -p
It looks like you are using Intego to restore information.
Since there is no Firefox folder, I would recommend a reinstall. But before doing this, please make a back up of the profile folder: this will have the file path for where it is on your Mac [[Profiles - Where Firefox stores your bookmarks, passwords and other user data]] - that is if there is a profile detected in the profile manager.