User-Agent: Mozilla/5.0 (Windows; Windows NT 5.1; rv:2.0b2) Gecko/20100720 Firefox/4.0b2 Build Identifier: Mozilla/5.0 (Windows; Windows NT 5.1; rv:2.0b2) Gecko/20100720 Firefox/4.0b2 After upgrading from 4.0b1 to 4.0b2, I am no longer able to access URLs using the location bar. I've attempted both pressing enter and clicking the go arrow. I've confirmed that it's an issue with only my profile, but the exact reason is still unknown. Reproducible: Didn't try I uninstalled Windows 7, backing up my Firefox profile first, and moved to Windows XP. Upon creating a new profile, I confirmed it's solely a profile issue. Perhaps something is screwing up because it's thinking I'm still running Windows 7.
Discovered cause and successfully reproduced. This and bug 582870 are caused by Tab Mix Plus.