continue the script until it struggles to select your huge inbox.

Thanks for that....I did try continuing the script a few times in the beginning but as it seemed to just stay locked up I finally gave up. I think once I get my new emails read, or placed in a folder, I'll try continuing the script again and try waiting it out.

I just noticed you mentioned Ctrl and Ctrl+A. but not shift + click to select. Have you tried Shift + select. Click to select and hold shift to click to select the the extent of the range between the two clicks? That would make the chunks larger than Ctrl and smaller than Ctrl+A.

You might also exclude the Thunderbird profile folders from anti virus scanning. Scanning often has a significant impact on the performance of Thunderbird generally, but in these sorts of situations the impact truly becomes noticeable

Check the Activity manager from the tools menu. Make sure it is not determining what mail to index, or indexing mail. Another drain on available computing cycles to do what you want. Given the wholesale deletion, It might even be worth turning indexing off entirely, options > Advanced > General tab.

While you are there turn off windows indexing of your mail. Another thing slowing you and it down. Unless you search your mail using windows search (cortana) leave it off. A setup dialog everyone clicks yes to without knowing it doubles the storage space used for mail and only benefits windows. Thunderbird does not use to data at all.

If you turn Thunderbird global search off for a time. Use the instructions here to reset the global database, otherwise it will return inconsistent results afterwards. It is simply deleting a file while Thunderbird is not running.

Hey Matt,

I wanted to be sure and write you back to let you know that even though it took some time....continuing to click on, "Continue" in the script window, it did work! And thank you again for that!

What's funny about that event was that going into it I knew that it would lock the computer up, or rather I'd get the, "Not Responding" message. So I would click on continue and it would not do anything...or so I thought, because I'm in my office at home and I had the TV going figuring that having it on would let me watch the TV while messing around with this issue.

So I look away for a minute after having clicked continue about 3 or 4 times, then I look back at the computer and low and behold I notice the number of emails had dropped from 19,643 to 16,543! I sort of did the double-take thing and the "well I'll be", and so I kept going like this and after every 3,4 or 5 continue clicks I'd notice the number of emails would drop, usually by a couple of thousand at a time. How weird I thought....but that's how it worked until finally I got down to 38 emails, or so it showed, but my inbox page still showed nothing but emails.

I did it one more time and sure enough my page cleared and all 19, 643 emails were gone. During this time I noticed that they weren't showing up in my "Trash" folder like I thought they should. But once the inbox page cleared all of a sudden they all showed up in my Trash folder. I just did the usual thing of, "Delete Emails," in the Trash folder and it only took a second or two and poof....they were all gone!

So your answer and solution worked....it might've been a little time consuming but who cares?! It worked. Its pretty scary and daunting to see over 19,000 emails in your inbox and I was freaking out when I first realized what had happened after switching from POP to Imap. I figured it might take a couple of months just clicking delete, delete, delete every time I had a few minutes to devote to getting rid of all of them.

So thanks again Matt.....Thunderbird is still relatively new to me after switching from MIcrosoft mail, which I couldn't use after getting a new computer with Windows 10. I'll forever be disgruntled with Windows and Microsoft after that fiasco. But Thunderbird seemed to fit me best after researching all of the other options available. Hopefully if I run into another issue with Thunderbird that's beyond me, you'll be around!!