ContributionsMost RecentMost LikesSolutionsMozilla Firefox wont open after upgrade. Error: The instruction at 0x77bc2245 referenced memory at 0x77f1748. The memory could not be read Is anyone else having this error? The instruction at 0x77bc2245 referenced memory at 0x77f1748. The memory could not be read. Good news, The problem is not with Cox or McAfee. In my case the issue came from additional anti Mal-ware software that I had installed, in my case it was (Prevx 3.0). I turned off my firewall (McAfee) and Prevx, then I uninstalled Firefox and re-installed it. I tried opening it without McAfee or my anti-malware software and it worked great. I turned back on the McAfee firewall and it stilled worked great. I turned back on Prevx and had same error message same problem. So for the time being I am just going to stick with McAfee from Cox and leave Prevx off. At a later time I may attempt to figure out what setting in Prevx 3.0 was causing the problem, if anyone has any thoughts or suggestions on this please let me know. Thanks Peacefulwaves peacefulwaves@cox.net Re: McAfee Security Suite I was having similar problems with the Google Chrome browser and Mozilla Firefox after a McAfee upgrade, however by altering a few settings in McAfee I was able to get back to normal browsing speed without any problems. To make the needed adjustments. 1) Open McAfee 2) Click on Firewall (this will bring up an option on the right hand side that says 'Settings') 3) Click on Settings 4) Then click on the down arrow next to "Internet Connections to Programs...(you should see a list of programs that use the internet come up) 5)Check the access for your broswer, if the access is set to Outgoing only instead of Full this could be the problem 6) Click on the browser (Mozilla Firefox or Google Chrome etc.) then click Edit then change the access from Outgoing to Full then click Save and exit out of McAfee 7)You should not have to restart your computer to see a difference, if you do restart your computer and are still having problems try following the above steps again, as after a computer restart for some reason McAfee tries to change the program back to Outgoing access only. This can also happen after an update to a new version of your browser. Hope this helps.