I am no tech genius and am struggling.... I have an old laptop (L1) and now have a new laptop (L2) - wanted to make my Thunderbird messages (POP account) accessible on both so installed Thunderbird on L2. The problem I then had was that if messages went to L1 or my phone they didn't come through to L2. So I went into my gmail through google on L1 and changed my POP settings, not really knowing what I was doing. I changed it to 'Enable POP for all mail (even mail that's already been downloaded)' and 'Keep Gmail's copy in the Inbox'. This resulted in every email I'd ever had since setting up my Gmail reloading into my inbox (20K messages!) on L1. I now get new messages on both laptops however nothing is showing in any of my L1 Inbox subfolders (I had everything nicely filed...), and on top of this if I make a new subfolder the folder appears but if I moves a message from inbox to that folder the message disappears i.e., it's not visible.... I restarted Thunderbird after this and got an error message 'Couldn't load XPCOM' but I can still see all my inbox messages so seems to be starting up OK but the folder problem persists. It's maddening as I can't sort out my 20K messages into manageable folders.... I'd really like to understand - in an explanation fit for a tech dunderhead - what's going on. Both to fix it, and to stop the same thing ever happening in my Thunderbird on L2.... It'd be much appreciated if someone could help me unravel :)