Reported steps to reproduce according to the users:

1. Ensure vertical tabs are enabled
2. Set vert. tabs to be minimized
3. Open enough tabs such that the vert. tab strip is scrollable
4. Close one of the tabs

☝️ Note that some users report not having to have the vert tab strip minimized.
Tabs and/or browser will stop responding. Likely has to do with Cr144.

https://community.brave.app/t/newest-update-broke-tab-scrolling/648197/12

just tried brave beta and it also freezes with vertical tabs on

Same issue:

Strange enough i found something im testing. if you go change animation settings in windows the problem has currently stopped. unsure if brave pushed out some update but its not crashed yet for me.... Still doesnt resolve the fact that there may be something seriously wrong with the update for interacting as such....

Enable or Disable Animate Controls and Elements Inside Windows | Tutorials

Yup I have same problem. Switched back to horizontal tabs and problem fixed itself.

Brave is up to date
Brave 1.86.139 (Official Build) (64-bit)
Chromium: 144.0.7559.59

I have 2 pcs with same brave versions.

Best way to reproduce this error is:
push manual restart button, while brave is opened with vertical tabs opened. Some file corrupts itself. And now I have 1 pc working fine and another corrupted. Also I have to note that those pcs are clones - hardware is identical 1-1. So I know that there is 1 file that corrupts itself after forceful restart, shutdown, power outage. Simply reinstalling doesn't fix the problem. Maybe only way is clean reinstall, usually works if you completely reinstall OS. Now I need to find a solution how to cleanly reinstall brave without OS reinstall.

I also tried to sync to another browser. Seems this corruption spreads to your sync chain.

Same issue.
Found one workaround to allow closing tab without switching to horizontal: scroll the vertical tab bar all the way up before closing any tab. Still quite annoying when closing multiple tabs but still better than suffering horizontal tabs.
Seems that as long as the tab count is reached such that the vertical tab bar allows scrolling, and the scrolling is non-zero when closing a tab, the browser will be not responding indefinitely. Some reddit comments suggested using a new profile; not working in my tests.

I never minimized the vertical tabs and it happens. It also happens if you click the restore window pop up after restarting the app. For Brave Beta (not tested for Brave regular), it also happens if you unpin a pinned tab. In fact, a bug of Brave Beta is that as long as you have pinned tabs, the vertical tabs become scrollable even if you only have a small number of tabs. These two bugs work together.

Last time my usage of the browser was broken after a Brave update is #41781. Since then I only update about once every one to two months. But now here's an even more serious issue. Brave needs to have a way to restore to previous version while keeping user data, as it has shown that it just can't keep updates stable. (If you try to install a previous version using the installer from github releases, it doesn't change the version.) Reference: #5576 (comment).

A "workaround" I'm using is to use multiple windows to reduce the number of tabs in each window and make the vertical tabs unscrollable. For Brave Beta you also need to unpin all tabs.

Still encountering browser locking up on Closing a tab in Vertical Tabs mode. No issues if Vertical Tabs is disabled.
Brave 1.86.142 (Official Build) (64-bit) Chromium: 144.0.7559.97 Steam OS: 3.7.19 (Steam Deck)

v1.88.53 contains the fix; not this version. Turning off 'Reduce Motion' or 'Animation Effects' mentioned in previous comments are just workarounds for v1.86.142.

Did you mean these workarounds not working?

No. I am using arch Linux. Steam OS variant. Disabled all animation effects.

Strange enough i found something im testing. if you go change animation settings in windows the problem has currently stopped. unsure if brave pushed out some update but its not crashed yet for me.... Still doesnt resolve the fact that there may be something seriously wrong with the update for interacting as such....

Enable or Disable Animate Controls and Elements Inside Windows | Tutorials

I can't get over the fact that enabling animation effects in Win11 settings fixed my Brave startup crashing issue.

Thank you so much.