Further to my problem in [http://example.com https://support.mozilla.org/en-US/questions/1424732] where I describe a problem I have with accessing my mail server, I now have a self-inflicted new problem which merits a separate post. I tried to fix the problem by uninstalling then reinstalling Thunderbird. I first put a copy of my Profile folder onto my desktop (it's 20GB, to big for the Export tool, apparently), uninstalled the product including my Profile and reinstalled Thunderbird. I then copied the backup Profile folder to the C:\Users\billh\AppData\Roaming\Thunderbird\ folder. I had assumed that the Profile would include all my account details (I had five accounts defined) and all the Local Folders where I have been archiving emails for 20 years, but none of these were restored when I started up the new Thunderbird. It was a blank canvas, asking me to define an account to get started, which I did. I have seen other solutions to this given on the forum but they don't seem to apply specifically to my setup. Maybe they are for older versions. My Profile folder backup has three subfolders: 1oltjdxc.default, 1oltjdxcBKP.default and 5g4thnfjORIG.default-release My new install (after I copied in the backup) has five: The above three plus ewa0dnv6.default and pkon61kp.default-release The previous solutions have been to look for files called 'prefs-n.js' where n is a number whose purpose I don't know, but apparently there can be more than one. Renaming the prefs.js file in one of the above folders to prefsBKP.js (or something) and renaming the prefs-n.js file that contains the account names to be included in TB to prefs.js seems to be the accepted solution. However each of the above folders except the '5g4...' and the 'ewa...' ones contain files called prefs.js containing references to the five accounts I had defined previously. None has a suffix number. The 'pkon...' folder has a reference to the one account I defined when starting up TB after the reinstall. I can't delete that account as TB won't let me. Hope that's not too confusing, but the bottom line question is - how can I get TB to recognise the prefs.js with the full set of accounts and (quite important to me) all my archived emails? I'm assuming the folder called 1oltjdxcBKP.default is the 'master', but surely it would have been used when TB started up the first time after the reinstall? However, it seems to me, perhaps, that pkon61kp.default-release has taken over from 1oltjdxc.default as the 'master'. Should I just rename the latter as the former (after renaming it as something else? And would it need a 'BKP' version too (presumably just a copy)? Grateful for any advice. Bill (Windows 10, latest version of TB)