I have used Thunderbird for years on several computers, including my Lenovo Yoga 2, without issue. I recently purchased a Toshitba P55W laptop (which I am regretting) and I cannot get Thunderbird to work decently. It crashes, locks up, wors very slow, and is taking close to a week to download existing e-mails in one account, where my Lenovo only took about 30 minutes for 5 accounts.

It is perplexing, and damned irritating!