I have Thunderbird connected to a number of providers including hotmail and OVH, all configured for IMAP. OS = Linux Mint Everything was working fine until I installed the upgrade to 128.4 offered by the Linux Mint update manager. Since then it takes a very long time to even send a simple email with CPU usage going up to or even over 100% (multi-cores). Even in normal usage with nothing happening Thunderbird is using 25% of the CPU. The sending process often times out giving a message that says the connection was lost to the SMTP server.