I opened TB on my office PC yesterday and noticed something very different about it; all of my inbox folders were missing. I initially panicked and thought I'd lost 4 years worth of saved emails (the ones in folders are the important ones!) but I checked the account on my iPad and thankfully the folders and messages are all still there, so it's a sync problem in Thunderbird. To check if this was an isolated issue, I fired up TB my laptop with no Internet connection, noting that all the folders were present, then connected it to the network and restarted Thunderbird. As soon as I did that, the folders disappeared. I have tried all the sensible things like starting the client in safe mode, with no add-ons, updating it, checking folder view settings etc. Nothing has worked so far, does anyone have any idea what I could try next?