Check you have the following selected: View > Folders > All View > Threads > All check there is no other filters operating. Select folder and see if the 'Quick filter bar' has any icons highlighted. If yes, click on highlighted icons to disable them. Please post images of the following. Image showing the Folder Pane and all folders in the 'Local Folders' mail account. In Thunderbird Help > Troubleshooting Information Under 'Application Basics' section - about 8th in list -Profile Folder - click on 'Open Folder' See image below as guide. A new window opens showing the contents of your profile name folder. Click on 'Mail' folder to see 'Local Folders' mail account folder Make sure the view is showing details and all folders and files are visible. Make sure the directory which shows what you have selected is visible, so I know where you are looking. Post image showing all contents of 'Local Folders' mail account. You should see folders with extension *.sbd Click on folder *.sbd to see contents Make sure the view is showing details and all folders and files are visible. Make sure the directory which shows what you have selected is visible, so I know where you are looking. Post image showing all the contents of that *.sbd folder Repeat for each *.sbd folder - post image. Then we can see what is contained, where it is stored and whether there are missing mbox files which are stopping a proper display of folders.