Your computer may have trouble distinguishing between the upper and lower case strings here. I suspect that you have two similar accounts but their names are what you are reporting here. If they are both going to the server for messages (and I suspect they are set to use POP) then they are in a race and the first one will win. I would suggest you go into Account Settings and change the ''name'' of one of them to make it unique; say [email protected] You should then be able to remove this account now that it has its own distinct name. Again, in Account Settings, select the unwanted account, then click the button at the bottom of the pane where the accounts are listed (this is usually labelled "Account Actions") and there you can remove the account. The same trick, changing one folder name to something else is sometimes needed when users want to tidy up folder names, specifically if just changing case. You can't just change "work" to "Work" because at some level the two words are interchangeable and it appears that you're asking it to create two folders with the same name. However the sequence "work", "work2" then "Work" gets around this. I think the same will apply to account names.