I've been using Thunderbird for years on macOS with no problems. All of a sudden, as of yesterday, I can't create new folders and subfolders. I also can't rename folders. The software is up to date (128.2.3esr (64-bit)). The laptop is running macOS Sonoma v 14.6.1. I've tried restarting Thunderbird, restarting the laptop, and Googling for an answer, of course. I've also tried opening Troubleshoot Mode, that didn't make a difference. I probably have several hundred folders - it's a work account and each client has to have their own subfolder. I can't seem to find anything that says there is a limit to the number of folders, and in any event that wouldn't explain the inability to rename folders. Thunderbird is working fine otherwise.