There is a reason we do not support Thunderbird profiles in "the cloud" now you are seeing one of them. Files systems on computers and networks are *not* the same. I suggest you take it up with dropbox.

Having a program running on your local machine synchronizing files is an issue in itself, as it does not know when a file update is truly done, especially in a case like Thunderbird were large files are edited every couple of minutes requiring new synchronization.

If you can replicate the issue on a non synchronized local disk, please say so, otherwise I suggest you file a bug seeking Thunderbird offer support for network profile storage.

Thanks for your reply. I will change the backup to dropbox. Do you know how it would be best to keep an up to date backup of the profiles folder in the cloud? I was thinking of placing a briefcase in dropbox and updating it on a daily basis?