All I can suggest it try the troubleshooting here https://wiki.mozilla.org/Thunderbird:Testing:Memory_Usage_Problems If you have an antivirus program scanning in the Thunderbird profile folder, that is the first thing to stop. It made my system unusable on an SSD drive. I found that helped. Rebuilding the global index has also been known to offer improvement for some folk. Other simply turn of the global search and indexer in settings While I have no real basis for this I would assume that disabling the integration option to allow windows to search mail probably would help as it removes the need to write a second copy of each email to the local disk. I turned off the option in the windows file manager for the profile folder and it's children to allow the windows indexer access to the files. At the time that also helped, but that was with a much earlier version of Thunderbird on a platter disk. All my actions have not ceased the periodic hangs and I continue to fluff about trying to end them. I have them to a simply annoying level, but I have been unable to end them entirely. Perhaps I need to disable the global indexer. Each time I look in the activity manager (on the tools menu) it is determining what messages to index.

lico44 If you are still having difficulty, please post an update.