I just ran into this as well. Starting it up, I get a blank update window. None of the buttons on that window do anything. Clicking the red X closes it, and the main browser window opens, which is mostly blank and equally non-responsive. Going back to the 20180927130926 release fixes it for me as well. Downloading a fresh copy of the 11-4 release doesn't help. I went through and disabled (but didn't uninstall) every addon, browser is still unusable.
I have no AV. Running windows 7. Here's a list of the addons I'm running:
Adblock Plus 2.8.2 true {d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}
Classic Theme Restorer 1.7.7.2 true ClassicThemeRestorer@ArisT2Noia4dev
Classic Toolbar Buttons 1.6.1 true CSTBB@NArisT2_Noia4dev
Cookies Export/import 1.0.1-signed.1-signed true
CookiesIE@yahoo.com
Download Cleaner 1.6.0 true jid1-LSHV456F7wAw9g@jetpack
Downloads Window 0.6.8 true {a7213cf2-fa1e-4373-88ff-255d0abd3020}
DownThemAll! 3.0.8 true {DDC359D1-844A-42a7-9AA1-88A850A938A8}
Element Hiding Helper for Adblock Plus 1.4 true
elemhidehelper@adblockplus.org
FindBar Tweak 2.1.12 true fbt@quicksaver
Firebug 2.0.19 true
firebug@software.joehewitt.com
FireGestures 1.11.1 true
firegestures@xuldev.org
FireStorage Plus! 1.7.1-signed.1-signed true
firestorageplus@nickbelhomme.com
Greasemonkey 3.11 true {e4a8a97b-f2ed-450b-b12d-ee082ba24781}
Image Zoom 0.6.3.1-signed.1-signed true {1A2D0EC4-75F5-4c91-89C4-3656F6E44B68}
KeeFox 1.7.2 true
keefox@chris.tomlinson
Save Session 1.3.1.6.1-signed.1-signed true
savesession@noasobi.net
Self-Destructing Cookies 0.4.12 true jid0-9XfBwUWnvPx4wWsfBWMCm4Jj69E@jetpack
Smart HTTPS 0.1.8 true jid0-oFwt2ZcakHhkFl7Kp4lJn@jetpack
SQLite Manager 0.8.3.1-signed.1-signed true
SQLiteManager@mrinalkant.blogspot.com
Status-4-Evar 2017.08.20.15 true
status4evar@caligonstudios.com
Stylish 2.1.1 true {46551EC9-40F0-4e47-8E18-8E5CF550CFB8}
Tab Mix Plus 0.5.5.0 true {dc572301-7619-498c-a57d-39143191b318}
Text Link 5.0.2016031501 true {54BB9F3F-07E5-486c-9B39-C7398B99391C}
The Camelizer 2.10 true
izer@camelcamelcamel.com
uBlock Origin 1.17.2 true
uBlock0@raymondhill.net
User-Agent Switcher 1.2.2 true
user-agent-switcher@ninetailed.ninja
YesScript 2.2 true
yesscript@userstyles.org
Youtube's Annotations No More 0.6 true jid1-ss6kLNCbNz6u0g@jetpack
YouTube High Definition 63.1.5 false {7b1bf0b6-a1b9-42b0-b75d-252036438bdc}
YouTube Video and Audio Downloader (Dev Edt.) 0.7.6 false {f73df109-8fb4-453e-8373-f59e61ca4da3}