Error std::exception

The bug is still there.
Occurs every time when browsing fonts in Character window. Possible font conflict.
MAC, AE 2025 (the most recent).
Basically the pop up window locks the software completely which requires force quit in the system.
Even if you don't know the reason of the issue you can probably change the behaviour of the error pop up window so it doesn't block the software.

This happened to me in 2025 2.2 after I accidentally scaled a shape layer to  155862045.684%

This just happened to me with AE 2025.2.2 (Build 2).  I was manipulating a shape, maybe grabbed a handle and made it really hufge for a split second. Then the popup. That's it.

Could you also try clearing out the following folder? 
~/Documents/Adobe/After Effects 2025/User Presets
This saves user created variations of plugins as well as saving additional plugin data. Maybe information from a previous install is corrupted or not valid and causing issues in your current install.

I followed the advice from @Jessica McMillan via this link: https://community.adobe.com/t5/after-effects-bugs/after-effects-warning-unknown-exception-using-effects/idc-p/14800068#M11551

And it worked. I hope this will help others who are experiencing the same problem as me.

I did this and the issue was completely resolved.

If you're using a Mac, go to System Preferences > Privacy & Security > Full Disk Access, click the + button, and add After Effects to the list. Restart the program, and the problem should be fixed.

I have dealt with a similar issue for hours. In our case, the problem was that certain font files had been removed from the machine. For example, Adobe Fonts were deleted during an update, but the application was still searching for them. We recorded the splash screen and slowed it down to see where it was getting stuck. While I'm not certain if this is the same issue you're experiencing, it might be worth checking to see if fonts could be a potential problem.

The same error has occured with once system. We have 30+ macs with After Effects in an automated envorment. I hope we don't end up with the same issue.

To get mine working, I had to backup and totally wipe my MacBook and reinstalled 15.4 and have not updated the OS or After Effects since. I had just gotten my MacBook a couple of weeks ago, so it was not a lot to backup, but still a pain to do. I hope it is actually fixed soon.

Same error suddenly after Sequoia 15.4.1 on both (2024) Macbook Pro and (2022) Mac Studio. Hope it is resolved soon!

Quick Update, since 5.2.2 the issue is resolved for me.