- Everything was going OK when looking at my very large inbox (27,331messages) earlier. - Then worked extensively reviewing old messages in Archive Folders. Everything looking OK in message listing. - Switched to Firefox which was also open and viewed a few pages and translated and .rtf file to .doc using Zamxar free online conversion service. - Switched back to Thunderbird again to look at my inbox and none of the messages show in the listing box. The messages are there but their Subject, From, Date, etc info is not listed. The box is blank. - As I run my cursor up and down in the empty message list box, message lines highlight and if I click, the message appears in the preview box. Everything is there but the listing is not displaying. Compacting folders did not help. - Archive and other folders previously created display their contents normally. - If I copy a file from the malfunctioning inbox to one of those old folder that work the copied file displays there normally. - If I create a new folder and copy files to it from the malfunctioning inbox or from a properly functioning old folder, files do not display in the file listing. They are there but don't display in the listing. - Restarting Thunderbird does not fix the problem. - If I exit Thunderbird and from Windows copy AN_OLDFOLDER and AN_OLDFOLDER.msf to AN_OLDFOLDER-Copy and AN_OLDFOLDER-Copy.msf then open Thunderbird again the AN_OLDFOLDER-Copy functions properly. (It of course shows in Thunderbird as a second AN_OLDFOLDER folder.) In Thunderbird I rename the second instance of AN_OLDFOLDER to AN_OLDFOLDER-2 and in Windows I immediately see AN_OLDFOLDER-Copy and AN_OLDFOLDER-Copy.msf switch to AN_OLDFOLDER-2 and AN_OLDFOLDER-2.msf . AN_OLDFOLDER-2 functions normally displaying the message listing. - I close Thunderbird and in windows delete AN_OLDFOLDER-2.msf and reopen Thunderbird. Thunderbird recreates AN_OLDFOLDER-2.msf but now when I look at AN_OLDFOLDER-2 the message listing is blank. It is misbehaving like all new folders I create. Looking at AN_OLDFOLDER-2.msf in Windows the recreated .smf file is 0 KB in size but after I compact AN_OLDFOLDER-2, AN_OLDFOLDER-2.msf shows 44 KB size. This is smaller than the originally copied AN_OLDFOLDER-2.msf file which was 56 KB. - Compacting the original AN_OLDFOLDER did not alter the ability to show the message listing. - Deleting one message and again compacting AN_OLDFOLDER did not prevent it from displaying the remaining message listing. - Apparently Thunderbird now fails to create a new .msf file from scratch but I don't understand why it stopped displaying my inbox listing. I had not deleted my inbox.msf file. That is all I have been able to figure out so far. I hope you can help.