Problem description: cannot delete messages using delete button, nor move messages to folders, nor send messages. No error codes or statements. Background: I have been a long-time user of TB. Two years ago, I began to use "Work Offline" since I have to work aboard ships at sea. In a single day, I work offline then go online for a few minutes to send emails, thus reducing my online time (which I must pay for). As time has passed, my TB has gotten slower, and now I have the problem above. I have had checked "keep messages on my computer." My profile shows folder sizes of 22 MB (Comcast IMAP inbox), 26MB (Comcast IMAP Sent), 50 MB (university g-mail Sent folder), etc. Confusingly, this same problem has happened to my wife at the same time. She accompanies me on trips at sea. Her PC: TB 24.3.0, Windows 7, alternating Work Offline and Work Online with a single IMAP email account from Comcast. My own troubleshooting: I have searched the Internet for solutions. I have taken these steps, with none producing problem correction: 1. Exit and restart TB. 2. Deleted all .msf files in folders and sub-folders. Restarted TB. 3. Automatically compact all folders when it saves 1 MB. 4. Remove the All Mail folder from the list of synchronized folders, unsubscribe it, exit, and then delete both "All Mail." and "All Mail.msf". 5. Ran TB in Safe Mode with Add-ons disabled. 6. Disk Defragmenter run. No defrag required. 7. There are no places.sqlite-shm and places.sqlite-wa directories in my profile. 8. There are no xul.mfl files in my profile. 9. I have set my anti-virus (Microsoft Security Essentials) to not scan my TB folder. 10. My inboxes have less than 25 emails. I regularly delete my Junk folder (after 10 days) and I delete emails older than 180 days. 11. I am using less than one-third of my hard drive. 12. I have uninstalled TB and installed a number of older versions, e.g. 17 and 24.0. Thank you in advance for your assistance.