Remove your old firefox profile and install new profile.

• http://kb.mozillazine.org/Creating_a_new_Firefox_profile_on_Windows

Have you already restarted the computer? The updater may have put a lock on Firefox and is interfering. But a restart usually makes the lock go away and let the files update.

If restarting the computer does not allow Firefox to run, maybe the update you downloaded was corrupted.

To erase the bad update files, make sure Firefox is closed and delete the files in the updates and updates\0 folder:

• C:\Documents and Settings\<user>\AppData\Local\Mozilla\Firefox\Mozilla Firefox\updates
• C:\Program Files\Mozilla Firefox\updates\

Now try to start Firefox. Let us know what happens.

I do not want to have to redo the profile. After all, that is supposed to be why the update option, as opposed to downloading an entirely new Firegox, is supposed to allow.

Oh, yes, when I reboot the computer, i get these error warnings that need to be cleared, something about dll something. Remember, this is 1 hour after updating Firefox. If Firefox has not finished installing the updates by then, then why not?

If I Reboot, and then start Firefox, I discover that it wasn't updated. I get the old one. It then tells me that a new update version, version 18, is available. Do I want to update Firefox? and the whole thing starts over. Believe me, after waiting all day for Firefox to finish installing the updates to 16 to version 17 once, I had long forgotten that it had not restarted. So I rebooted that day to clear off what Windows doesn't seem to know how to clear, got the same result. I was trying to update v. 16 to 17 for about 2 weeks before I finally gave up and downloaded 17, removed 16, and then installed 17. I should not have to do the same for 18.

If the update is corrupted, then all updates are corrupted, no matter the time of day or night I download them. However, the entirely new program, latest version is not. Does that make sense? Usually updates are made up of smaller files, and the whole program is much larger. So don't tell me that the updates are corrupted because, obviously, others can download them easily. I have broadband.

I finally decided to test if my AVG anti-virus software or the IOBit Malware Fighter software was interfering and I disabled them temporarily. I rebooted, then disabled those programs, and then opened up Firefox. It was version 17.0.1 as usual, not updated. I went to Help, About Firefox, clicked on check for updates. It downloaded updates, asked to restart Firefox, and after Firefox closed, I got the window which said it was installing the updates, for the first time for either attempt to update to version 17 or 18. It installed the updates and actually restarted without any trouble.

I was going to disable all my add-ons for the next try. I never had to disable my AVG or IOBit before and they are the latest versions, too. AVG is the same version that allowed the update to v. 16 before. So something is different about both Firefox 17 and 18 that it won't allow updates with AVG in effect (or possibly IOBit Malware Fighter).

Yeah, I think you're right. It may be conflict with AVG. What version is your AVG Antivirus?

The only thing I can find on it is AVG Free Edition 2013, they have changed the interface enough to make it not quite as easy to find this information.

Oh, yeah, obviously it was an older AVG version when I had the same trouble updating Firefox v. 16 to 17.

Yes, see above under Chosen Solution.