Two possibilities occured assuming AV did not delete anything. Old Profile could not be opened for some reason and a new empty one was created - hence asking you to create a mail account. Old profile was accessed ok but for some reason thunderbird could not open the original pop mail account. So, can you provide the following information and I'll see what's going on. In Thunderbird Menu app icon > Help > Troubleshooting Information Under 'Application Basics' - at the bottom - click on 'about:profiles' It opens in a new tab listing all profile name folders. Make sure window is wide/high enough to show all contents. Post an image showing contents of that window. For each 'profile name' it will have 'Root Directory' and an 'Open Folder' button. Click on 'Open Folder' to see contents of profile name folder. click on 'Mail' folder It will list pop mail accounts and 'Local Folders' mail account. Post an image showing contents of 'Mail' folder. Select pop mail account folder. Select to View 'details' and make sure you have 'Type' and 'Size' column enabled. Post image showing contents of 'pop mail account name ' folder. Repeat the above for each 'profile name' folder. The requested information will tell us if you had an old profile containing pop account that have good folder size. It will also tell us if you are still using the old profile but not using the old pop account. Once this is known, we can advise on what to do next. It might be a case of reselecting and resetting a profile as default or pointing a new pop account to look at an old pop account. Or perhaps move old pop files into the new pop account. In addition, can you tell me: Does the new pop account have Account Settings > Server Settings to 'Leave message on server' ? Did you have a load of emails in 'Local Folders' mail account and can you still see those emails ?