I've been trying to transplant my Thunderbird profile from a computer running Windows XP to a computer running Windows vista. Both machines have Thunderbird 53 installed. The profile is large, with multiple IMAP and POP and Usenet accounts, and a lot of emails stored in "Local Folders" as well, so it's not feasible to rebuild it all by just re-create all the accounts on the new machine, one at a time (41 different accounts). And that wouldn't work for "Local Folders" anyone. So I need to transplant a copy of the profile to the new computer and get Thunderbird to recognize the profile. However, profile transplant has consistently failed. I wasted over 5 hours on this (from 1AM to 6AM Thursday morning) with nothing but failure after failure. My transplant technique is simple: 1 I drop a copy of the profile being transplanted (wuerhbg9.default) into the C:\Users\UsrName\AppData\Thunderbird\Profiles folder. 2. I change the "Path" in C:\Users\UsrName\AppData\Thunderbird\profiles.ini from "vrbq8vzg.default" (the skeletal profile created when I installed T'bird on the new machine) to "wuerhbg9.default" (transplanted profile). 3. Start T'bird. The failure is always the same: T'bird recognizes all my accounts and folders, but gives an endless string of "unable to open summary file for Inbox" errors. If I let it run for a minute, it first erases all my folders, then recreates them, then DUPLICATES them (each folder has a duplicate with the same name except for a "-1" suffix, eg, "Forums_Facebook" and "Forums_Facebook-1"). If I click on any of the folders, I get "Unable to open summary file for inbox", "Unable to open summary file for Forums_Youtube-1", "Unable to open Summary file for Forums_YouTube", etc, etc, etc. I thought it may be a permissions error, so I made sure that my current user id "owns" the entire "C:\Users\UsrName\AppData\Thunderbird" folder tree and all of the subfolders and files in it. I also made sure that all files and folders have permisisons set so that all of the following get "Full Access": 1. Current user id 2. Administrators group 3. System That's the same permissions as on the "skeletal" profile, which works. So I don't think it's a permissions error. So, why can't T'bird open any of the summary files (I assume it means the "*.msf" files?)? And why does it first erase all of my folders and emails, and then re-create them, and then DUPLICATE them? I need to get this working, as the old machine is too slow, and Local Folders can't be "re-created" as they exsit on one machine only. Anyone have any idea of what's going on here?