My recipients receive the mails I send multiple copies (10-15).
Cause of problem:
Outlook can not move the files in 'outbox' to 'sent items', so the messages remain in outbox, and sent into loops.
Cleaning up the Sent Items folder (especially mail with attachments), once cleaning is complete, launch option:
File> folder> compact all folders.
Create a new folder in Outlook Express (File> New> Folder) and call save-sent.
Move all mails that you want to backup 'Sent Items' to 'save-sent'.
Close Outlook Express.
Go to the folder containing the .dbx files(to find it, make tools, options, maintenance, storage folder, or do a search for *.dbx files.
Note: If this is the default configuration the files are probably hidden. To make them appear,go to Windows Explorer: Tools> Folder Options> View> display hidden files and uncheck 'Hide protected OS files'. (Remember to put these options in place once manipulation completed ).
Rename .dbx files in Outbox to .bak format(Sent items )
Restart Outlook Express, it will automatically recreate the outbox and sent items files.