I have used Thunderbird on and off for years with Windows XP, Windows 7, and now with Windows 10. It has ALWAYS been slow to download IMAP mail from Inbox.com This has been with every version that I have tried, both production and beta. I have uninstalled and reinstalled versions over and over. I have changed motherboards. I have tried configuration tweaks in Thunderbird. I have rebuilt Thunderbird indexes. I have troubleshot on and off over the years. It is always way way slower than Outlook 2000, Outlook 2010, and Outlook 2016. With Outlook 2016 I can download approximately 20,000 emails in about 2 hours from Inbox.com. The exact same emails take many many more hours to download with Thunderbird. I am currently using Thunderbird Beta 99.0b1 64 bit. Is there any potential fixes for slow download of IMAP email with this program other than what is usually found in FAQ's?